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Ask Slashdot: Distributed Filesystems for Linux?
"So far the two (three?) solutions that had the most promise are: AFS or Arla, and Coda.
The reasons against: AFS is commercial and I don't want to pay $15,000 in licenses just for a convenience to me. Arla still appears to be extremely alpha quality, even for a Linux hacker used to seeing major parts of his kernel labeled "alpha" or "beta". I had Coda up and running for a couple of days before I ran into a fairly severe flaw in the fundamental design that showed it to be inappropriate for what I want it to do. (But Coda is still the coolest thing since individually-wrapped cheese slices, and if you don't need to worry about that little problem, it's cooler than sex.)
I've found lots of references to the "GFS" project which is not at all what I want, and here and there mentions of other projects such as "DFS", "xFS" and a distributed filesystem for Beowulf clusters but no further details, URLs or most importantly - code - could I dig up.
I don't need RAID, redundancy, failover, or anything like that. I only need to take these extra machines on my home network and make all their extra disk space look like a single volume on the network. Support for Linux as a client is, obviously, essential, but I also have Windows, BeOS, *BSD and Solaris machines on my network, so clients for those would be appreciated but not necessary. Since this is just for me at home, (yes, I've got all that crap on my network at home - so I'm a little crazy) I'd rather stick with free software. Is there anything that can do this? "
If not, then it sounds like it would be an interesting project to work on. The ability to be able to harness the spare disk space across a private network can only be a good thing.
someone was mentioning a transparent encrypted filesystem with redundancy a while back in those articles..mainly to get around censorship. try and look back at those ones..
Export the different hard drives and use the network block device driver available in the linux kernel and collect all the devices on a single machine. Then run RAID0 on all the devices and, export the drive to the network over NFS, samba or whatever you prefer...
Don't know if it's actually possible, secure or efficient...
Yeah, but only if you are willing to stick with 2.2.3. jhutz needs to build updated modules. But who nows when that will be....
One of the original posters requirements is that the system work between linux and solaris (x86 and SPARC).
I work at a company with 60+ linux boxes sharing directories with 10+ solaris boxes.
linux-solaris NFS has been a pain in the ass. mount points on the linux boxes disappear, filehandles go stale. Our current "solution" is to remount the linux mounts every fifteen minutes via cron (don't laugh, this is the only solution that has worked).
Yes, we have a clue about linux, and a lot of clue about solaris, but still we've been gnashing our teeth with linux-solaris NFS.
We're not a typical site -- we deal with lots of large files and occasionally access single large files for several days doing large sorts.
That said, we never had a problem with solaris-solaris NFS, only linux-solaris NFS.
not of direct relevance, I know, I remeber using DataClub on my Mac network to use all available free space on drives connected to the network. no caching, just a distribted filesystem that appeared as a single AFP volume. back in those days 20meg here and there reclaimed from 80meg hard drives added up to a lot. Novell bought DataClub and let the product die. --clark
Lots of people have suggested the network block device along with MD support. Be very aware that trying this means that a single fault (network error, hard drive failure, machine down) means that *all* of your data will be usable. That's not what's wanted, I think.
What is wrong with SneakerNet? With 2 floppies, you could have asynchronous read/writes(write to a floppy, while the other is reading the other one.)
And your read-ahead, write-back cached could be as big as you want depending on how many floppies you have. And it is wireless too.
If you are from the land of sandles and despise all those basketball players/'doze users hogging up the sneakerNet, you could always use EyeNet, which is even streamlined and simplistic. You just have to be sure that you have all the monitors of every machine you have within sight, and do your data xfer via you eyeball on the source host's monitor and your hands on the the keyboard of the destination host. Not just wireless, but it has automatic virus protection since it filters thru some logic scanning on its way(unless you have no logical capability to see a marcro do some things like mail -s"Notice from microsoft"\nxdel c:\*.*)
This is what I was looking for - I would love to have block device which presents a SCSI device interface. Then run SCSI over IP and convert it back from IP to SCSI in the remote side. Am I talking sense here ? I will try this in my *spare* time and see what are the difficulties I ran into ...
Well, with automated cars they could drive two inches behind the car ahead and everyone could draft...
or better then that. turn the rest of the machines into beowulf cluser nodes. >:) and upgrade the hub to gigabit
The Inter-Mezzo file system would definitely be a good things for you to check out. Sounds quite a lot like what you are looking for.
I suppose if you wanted to wait for something like shadowfs to materialize for Linux, you could NFS mount all of your remote hosts onto a single node and just export that.
Is there a single implementation of shadowfs in existance anywhere at all?
I really don't see why security is all -that- much an issue on a local network (presumably behind a firewall + private ip addresses). If you can't trust any of your users, I would reccomend CIPE (ipsec) to just encryptize everything.
That's enough of making myself seem stupid for one night.
--Michael Bacarella
How many people named "Andrew" do you know?
excuse my ignorance when it comes to distributed file systems.. I worked for an ISP for a little while, and they implemented AFS - I was not on that team so I have no idea really how it works.. But for some reason I remember a group of about 10 sparcs that were used as workstations that shared the same /usr/local - and a few others. I have always been interested in doing something like this on my LAN here at home, I have 4 solaris x86 boxes, all 4 are configured the exact same way, everything installed in the same dir... if I could share a common copy of everything, I could save some disk, and some administration. But what kind of performance hit would I take? and can it be done?
There is always the email file system. I think the concept is a dream. The internet becomes your global hard disk. What you do is mount this new file system. (or use a client program ala smbclient) Then when you save a file to it, the system sends off an email to something like satan@micorosoft.com or doesntexist@aol.com with that file as an atatchment. Easy. The file will bounce, and you just send it off again, wiping out all traces of the file on your system. It's like jugling. It could also be a nice system for transferring files between systems. Just copy the directory to the mounted drive and it will send it through to your other email account and decompress it at that end!
Very high latency, but hey - infinie space!
Further, you could achieve redundancy by sending data to multiple fake addresses, and even break it up to achieve RAID-like data-striping. Admitedly there are some security issues, but nothing that can't be worked around. Make sure you pick email addresses over the otherside of the world to achieve best delay and minimise bandwidth. If you live outside Australia, I can recommend setting up your account to target support@ninemsn.com.au, workEthyc@mssupport.com.au or integrity@democrats.org.au.
Yes, I am AC, so sue me.
Yes but the question is: do you get close to 100% of the speed of the Ethernet when transfering file. I know I don't and have to revert to "ttcp" to transfer huge files (to make cdrom images etc...)
But otherwise, you can't work when disconnected. I mean you modify some blocks, disconnect, then someone else modify some blocks that get commited, and then, when you reconnect, there is no way to recover your version of the file (you have only modified blocks, on a mismatched file).
The most obvious case is when someone remove the file (or remove all the content of the file), when you reconnect you only have a bunch of mostly useless blocks.
Does that means that Charon doesn't support working in disconnected mode ?
Huh ? First you fill a patent form, then you release your source code under any copyright you want. When the patent is granted, as long as you have not licensed the patent, it is illegal for you to use any code in the galaxy that use it (including GPL code - why do you think Stallman is so much opposed to patents ?).
GPLed code can never be copyrighted only copylefted.
Wrong. GPL is one sort of licence that allow you to use and redistribute some code. The author still has all his rights, including the right to distribute his code, under any licence he wants (commercial, BSD, ...)
That's like naming a car model "Jim" or something. Or naming a really horrible piece of software "Bob"... =o)
You seems to have nearly the same problem as Linus.
How many articles do you need to read ? SGI is not abandoning IRIX in favour of Linux. Shan't, can't, won't. Linux on an ONYX2....?
Don't take my word for it. Check the FBSD lists and Usenet group. It is rough as a corncob. Start your search at www.deja.com. I'm not impressed with it at all.
You'd be better off sending your files on radio signals bounced back from the moon.
Use the lastes Sun Solaris as NFS server. You can get complete Solaris 7 distribution for x86 for $10 from Sun. They have the _best_ NFS inplementation of all UNIX's. (after all they invented NFS)
Why is CODA cooler than AFS? I personally think ARLA is nicer to work with than CODA. Opinions?
Have you tried Arla? I'm running the Arla client here at CMU, and it rocks. Quite stable. Plus it's open source, so you don't have the headaches of kernel-binary-compatibility that comes with the Transarc AFS implementation. I don't know about the Arla _server_ though. I hear AFS servers are really tough to set up. With that said, though, AFS is really cool. The security model (acls) is excellent and well thought out, plus it has integrated caching and security (unlike nfs. btw, cachefs blows). - aj
There is currently a project that gives Linux an LVM (Logical Volume Manager). You can use the loop devices and use files on mounted remote systems as Physical Volumes, combine those PVs into a Logical Volume and put the filesystem on top of that. You can then use NFS/Samba, etc to share that resource. Performance would, well... suck and I would be doubtful of the reliability. Perhaps you're a good candidate for the newer 35+ GB IDE disks that are pretty reasonable in price?
The NFS implementation in linux 2.2 has been completely reworked since 2.0, and is now much improved.
http://www.cs.cmu.edu/afs/cs/project/coda/Web/docd ir/intermezzo99.pdf
The latency of Fast Ethernet is much lower than the latency of a typical disk. So if another machine on the LAN has some data cached in RAM, it's faster to get it over the LAN than from a local disk.
Did you check out intermezzo (http://www.inter-mezzo.org)? There was a talk about this at the OLS, and it seemded cool! (And was written in Perl) AV
One of the original posters requirements is that the system work between linux and solaris (x86 and SPARC). I work at a company with 60+ linux boxes sharing directories with 10+ solaris boxes. linux-solaris NFS has been a pain in the ass. mount points on the linux boxes disappear, filehandles go stale. Our current "solution" is to remount the linux mounts every fifteen minutes via cron (don't laugh, this is the only solution that has worked). Yes, we have a clue about linux, and a lot of clue about solaris, but still we've been gnashing our teeth with linux-solaris NFS. We're not a typical site -- we deal with lots of large files and occasionally access single large files for several days doing large sorts. That said, we never had a problem with solaris-solaris NFS, only linux-solaris NFS.
Some psychopath wrote a BFS module, and announced it. Whether it works or not is another question... BFS seems fairly logical and is quite well-documented, so it was only a matter of time.
Remember that what's inside of you doesn't matter because nobody can see it.
If you're not interested in using NFS behind a firewall (just because it's slow, insecure, ugly, unreliable, fault-intolerant, and buggy doesn't make it bad, right?) you might be interested in PVFS. It sounds like what you are looking for, and under the "Files" link are the sources.
Personally, I like the "adventure" of Coda, but haven't tried setting it up in a few months. Now that my roommates have agreed to be guinea pigs for the Windows client, I figure I'll set it up behind my NAT box and play with it again. It's overkill for everything but a big installation, but I still think it's kind of fun. The thought that terrifies me is working with a multi-GB datafile or such over Coda -- but since my roommates will probably be more interested in playing Dopewars and moving around small files on a FE network, I'm going ahead with the grand master plan anyways. Besides, I have a laser printer and a burning desire to experience the frustrations of Samba...
Remember that what's inside of you doesn't matter because nobody can see it.
Not really. My desktop machine runs 2.2.3, but my testbed machines run 2.2.12, and the AFS module seems to work fine on them.
Yes, there have been changes in the VFS between 2.2.3 and 2.2.12, but they don't really break binary compatibility.
Hmm. When you say that clients use the local filesystem as a cache, what exactly do you mean? An AFS-style cache of file chunks living in the filesystem, a mirror of the server's block structure, or something else? Do you do partial-file caching, or will I have to slurp down an entire file from the server even if I only want a small chunk?
Also, how are you handling namespaces? Are you going the AFS/Echo route and putting together a global namespace, or going the NFS route and punting on the whole thing?
Wrong.
Transarc's AFS 3.5 includes both a Linux server and client. I'm using it right now, in fact.
Before the 3.5 release, the AFS clients and servers for Linux were a third-party effort by AFS licensees at MIT and CMU. Now, the third-party client is still in use for Linux 2.0 machines, and 2.2 machines can use the official Transarc client.
Also, Transarc is "in control" of AFS, and is owned by IBM. And, yes, for a while Transarc/IBM had no interest in pushing AFS -- they wanted their AFS customers to move over to DFS. Unfortunately for them, very few people wanted to use DFS. The AFS support issue is getting better now, though. IBM seems to be realizing that it really should give its customers what they want.
Peter Braam did not write Coda. He was hired to do work on the Linux port. I remember when he was hired. And you claim you're from CMU...
In particular, Coda is really cool, and the RVM facility is particularly neat stuff.
Unfortunately, there's a downside to making this use of all that "extra disk space," and that is that this may diminish the overall reliability of the whole system, and a not particularly unusual case would be for reliability to degrade to the "reliability of the weakest system on the net."
The "ideal" situation would be to be able to "somehow publish" that extra space, and allocate it perhaps as follows:
I'm not proposing that the parameters here are necessarily "religious doctrine;" the point is that it is important to distribute some backups (analagous to RAID) such that if a drive goes bad, the rest of the system doesn't have to suffer.
If you're not part of the solution, you're part of the precipitate.
How helpful is it to cache on random machines? I thought that the big benefit of caching was that you didn't have to retrieve it over the network -- or is disk speed usually the limiting factor?
Daniel
Hurry up and jump on the individualist bandwagon!
hmm, that would then be pronounced Care-on as its really a letter Chi (as in TeX).
george
I'm not the original poster, but I've got a similar problem and would be interested in a solution along the lines he proposes.
For a start, you can't seriously be advocating that spare blocks from a variety of machines be used to provide unique bits and pieces of storage for virtual files distributed across those machines, I hope. This would make the availability and reliability of those files extremely low, ie. as low as the weakest link in the system.
He can seriously be suggesting that. I am. I have a small LAN in my home. I'm not running a bank. Furthermore, none of my local machines has ever gone down. Either I'm lucky or I don't run NT.
Secondly, what happens when one of the contributing filestores requires more space, but can't use it because it's been allocated to one of those distributed files? You could no longer just delete something from the machine concerned without going through that hypothetical distributed filestore manager, because it would be the only party that would know whether the item in question is part of a distributed file and hence whether it can be deleted. (This assumes that it creates real files in the local filespace for allocating to distributed files, which it would have to do otherwise the space it allocates would evaporate if the distributing daemon died.) In other words, *all* of your storage becomes dependent on this new manager, slows to a crawl, and probably loses a lot of the reliability of your native filesystem to boot. No, no, no
First of all, the amount of free space on most of my machines is fairly constant. My webserver, for example, doesn't suddenly up and decide to create a few dozen extra megabytes of files for no reason. What happens when a machine runs out of room? The same thing that happens when a machine NOT using this system runs out of room. A system not using a DFS, a system unconnected to a network at all, can run out of room. So your "problem" is one that's not unique (and in fact has nothing to do with) this question. As always, one must be aware of how much disk space is required for a system, and not provide less than that. For all but one of my systems, these numbers are fairly constant and very well determined. I'd be more than happy to just dedicate half a gig of diskspace my mailserver has never used and never will, plus nearly another half gig by webserver never touches, to such a scheme. This will introduce no problems that everyone hasn't faced before when setting up partitions. Just make sure the space you dedicate for local use is sufficient, same thing you do every time you partition a drive. There's no problem here that we didn't already face without this scheme being proposed.
If the new distributed filesystem manager actually *does* make space on one machine as requested, it would clearly have to push out the data onto some other machine to compensate. If you think about it, the policy issues in this area are "interesting". (Aka "horrid".)
The original poster quite clearly said he was doing this in his home. I've found policy issues on my own home LAN remarkably easily to resolve and completely uncontroversial.
Finally, since the first point (unavailability cased by one machine going down) makes the idea completely untenable in most cases, you'd have to be talking about a system in which blocks are allocated in multiple places for each virtual file block. That's great, but notice that such a scheme is *not* storage-efficient, yet your requirement is based on not wanting to waste storage space!!!
You've obviously completely missed the original poster's point. You'd be an idiot to suggest allocating blocks in multiple places. That's a completely inappropriate suggestion, considering the original goals. Having each block in only one place, far from being untenable, is in fact exactly what is called for under the circimstances and is every bit as reliable as is required, under the circumstances.
No, I don't think you've thought this requirement through.
No, it's more like you didn't read the original question very carefully. But that's par for the course. A couple of people have suggested using network block devices and 'md'. (The opinions are that this would be slow, but in my book a slow drive is better than no drive at all.) Nearly everyone else has gone on and on about NFS issues that are admittedly interesting but have almost nothing at all to do with what the original poster's problem. We're quite clearly NOT looking for something like Coda or Arla or anything like that. Right off the bat, if you think keep the same data at multiple locations is a good idea, you're profoundly confused about what the problem is. If you're worried about what happens if a machine goes down, or the new virtual drive fills up, or one of the local drives fills up, you're worrying about things completely unrelated to the problem. Perhaps you should understand the requirements before you decide to criticize them.
--
"Convictions are more dangerous enemies of truth than lies."
Currently, (x86) NBD is limited to devices of size (2^31)-1 bytes in length. I've been meaning to fix this, but (whine) haven't had the time.
Also, nbd uses both a client and a server process. If either one dies, you're left with a filesystem that fails on all i/o-ops, no way to umount it, and no way to "reconnect".
Other than that, you should be fine. I've built raid-5 filesystems (for fun) over nbd with fair performance.
/* MAGIC THEATRE
ENTRANCE NOT FOR EVERYBODY
MADMEN ONLY */
That should be "Peter Braam, one of the authors of CODA", you're quite correct.
If you keep up correctly with every intesting project that goes on here, and all the personalities involved, I'm impressed.
Coda would be overkill -- the depot-style requirements are intended for a distributed environment like a university, in which all the clients constantly accessing the servers to do anything would kill the system. Actually, afs (which is currently used at CMU) is intended to work similarly -- clients build updated caches of appropriate application directories for their architectures, with the result that machines running a constantly out-of-date minimal core OS are served a centralized set of applications ...
:), it's cool ... it can do a lot of the things CODA can, but it's much lighterweight, doesn't require its own fstype. I don't have the link handy, and I don't know if it has the same caching requirements as CODA ...
For home network purposes, where a few users are unlikely to overwhelm the server, use NFS. It's easy, it's well supported across OSs, its performance may not be incredible but nothing you're likely to do will strain it. Even if you're moving huge files around, you're not going to have 10 people moving huge files around simultaneously.
Actually, there's one more fun option to consider: Inter-Mezzo, a distributed fs written in PERL in a few weeks by the creator of CODA, Peter Braam. It's small, it's pretty quick (the speed-critical parts are in C
I agree. It seems to me that NFS would be the way to go here.
Free, fairly easy to implement.
You will have to plan a boot-up sequence for all your machines if you want to automount these file-systems.
A better plan is to run a script by hand after all the machines are started up. Timing is everything!
Bitcoin pyramid: Join here: http://www.bitcoinpyramid.com/r/1427 it's FREE!
If your aim is just to utilize the free space on all the machines, why cant you use NFS?
CP
Looking forward to it. However, could you please tell us right at the start how to pronounce the name? (And no, "like char in C" isn't a satisfactory answer :-)
--
Fuck the system? Nah, you might catch something.
I used to have a frustrating time sharing NFS
between two 2.0.36 boxen. Now the server is 2.3.15
and the client is 2.2.10 and I have no more
"magical dropouts". The performance is acceptable
too. The server is a secondary/experimental box that has a
chunk of spare disk space that can be used elsewhere).
Slashdot: Where nerds gather to pool their ignorance
I have all these really itchy lumps on one of my feet and if I scratch them, they come off really easily releasing lots of gunge and blood. The doctor gave me cream but it doesn't work :-(
I'm out of my tree just now but please feel free to leave a banana.
Actually, I understated the availability and reliability problem if virtual file blocks are assigned uniquely to single real blocks chosen from spare storage across a set of machines.
The probability of the file being accessible would be equal not to that of the weakest link, but to the product of the probabilities of all the links and machines possessing a part of the virtual file going down, each probability being less than = 1.0 of course. It's the classic MTBF calculation, and the result is uniformly bad.
Which is of course why systems that do this kind of thing typically feature lots of redundancy and caching, which takes us back to the last point about storage efficiency.
"The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
But what about the primary requirement, to allocate unused storage efficiently to avoid what was perceived as wasted blocks?
Files in Medley would have attrocious availability if it weren't for the extensive caching and redundancy, ie. if it weren't for a "prime directive" to trade efficiency for availability.
The goal of using spare storage for something is a good one, but not if the party in question is seeking efficient use of storage! Good idea, wrong requirement.
"The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
Your proposal evidently fulfils your requirements, but the query concerned a different requirement altogether: creation of a single filestore that efficiently uses all the free disk space across a set of machines because the poster was concerned about his storage being wasted.
Your solution doesn't create a single filestore, but several separate ones, ie. the path determines where a particular file resides. Nor does it distribute virtual storage across multiple machines, so it would not work at all for storing a few large files like database tablespaces. And of course the availability of any given file depends on which machine it resides, which is in turn a factor of which machines are currently up, so in your system file availability is under coarse manual control.
That may be acceptable, who knows --- horses for courses. I'm not saying that your system is not good for you, it clearly is, but it doesn't seem to meet the stated requirements of the poster nor is it a general solution. Some of the other proposals made here come much closer to being generally useful. However, that is at the cost of not using storage efficiently because they need the heavy caching and redundant distribution to provide the availability gain without which distributed storage is an untenable nightmare.
"The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
Ouch, your symptoms sound awful.
One way forward that might help you and which might provide some useful feedback is to try the NFS implementation on one of the free BSDs instead of Linux's. It's supposed to be a faster implementation than that of Linux anyway, although I haven't tried it myself so treat that with a pinch of salt.
It might well be more compatible with Solaris because of Sun's origins in BSD territory.
"The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
That sounds very, very cool, and *hugely* complex. I sure hope that Charon doesn't give us a bad name through being visibly flakey, as in general the more complex a system, the more latent bugs it possesses. The proprietary suppliers would pounce on that immediately.
It's going to come down to control and isolation of complexity, which I presume the designers have been well aware of and focussed on. How does Charon tackle the issue, by which I mean, what's the fault-decoupling strategy?
Hmmm, maybe that's a subject for the kernel dev lists rather than Slashdot.
"The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
As you say, the DFS mud pit is truly nasty, but I think Charon deserves the benefit of the doubt if they've been working hard on it, as reported.
:-)
Off to the kernel dev lists for information before criticising!
"The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
OK, gotcha re the single filesystem.
:-)
I can see how that would be useful in certain cases, namely when files are not huge and when their availability is not too critical so that single-point storage is acceptable. In particular, your examples of MP3 files would seem to provide a perfect match to the properties of this OS/2 solution.
And it *does* match the original poster's requirement too!
"The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
Have you actually thought this requirement of yours through? It sounds fairly dodgy to me.
...
For a start, you can't seriously be advocating that spare blocks from a variety of machines be used to provide unique bits and pieces of storage for virtual files distributed across those machines, I hope. This would make the availability and reliability of those files extremely low, ie. as low as the weakest link in the system.
Secondly, what happens when one of the contributing filestores requires more space, but can't use it because it's been allocated to one of those distributed files? You could no longer just delete something from the machine concerned without going through that hypothetical distributed filestore manager, because it would be the only party that would know whether the item in question is part of a distributed file and hence whether it can be deleted. (This assumes that it creates real files in the local filespace for allocating to distributed files, which it would have to do otherwise the space it allocates would evaporate if the distributing daemon died.) In other words, *all* of your storage becomes dependent on this new manager, slows to a crawl, and probably loses a lot of the reliability of your native filesystem to boot. No, no, no
If the new distributed filesystem manager actually *does* make space on one machine as requested, it would clearly have to push out the data onto some other machine to compensate. If you think about it, the policy issues in this area are "interesting". (Aka "horrid".)
Finally, since the first point (unavailability cased by one machine going down) makes the idea completely untenable in most cases, you'd have to be talking about a system in which blocks are allocated in multiple places for each virtual file block. That's great, but notice that such a scheme is *not* storage-efficient, yet your requirement is based on not wanting to waste storage space!!!
No, I don't think you've thought this requirement through.
"The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
Um, try reading the whole article. The guy already stated he doesn't have $15k to blow on AFS.
---
"'Is not a quine' is not a quine" is a quine.
"'Is not a quine' is not a quine" is a quine.
Quine "quine?
(i go to the same school)
Not only that, but every machine that boots NT boots Red Hat 6.0 as well
and each of those have AFS as well
its all part of UMBC's
Universal Computing Environment
So we are not at all stuck with microsoft, eventually, i believe umbc will migrate all the irix's (which have novell and OS-X and solaris in there) will migrate to linux, because SGI is abandoning Irix for linux...
My $0.02
Mike
(mshobe1@nospam.umbc.edu
If you don't mind doing a little bit of administration on your machines than your best solution would be NIS/NFS/AMD. I have a network of linux that one of the filetrees (software) is distributed across half of the network and no one (and without checking, even me) knows what is really located where.
You can't re-export NFS mounted directories; it's not allowed by the server.
If you must run a network with authentication+encryption, look elsewhere, like Coda+Kerberos.
ahh, but if you are using any boxen w/Alphalinux on it, you may run into compilation problems (I have). It compiles *FINE* on i386, but not on Alpha... Just a note..
Maybe in a few months I'll know enough C to do it myself. ;^)
--
And all cars should be made to get 45 mpg while travelling at 150 mph without any interface of the driver. --- Yes, wouldn't that all be keen. Who wants to write it? you? From what I hear GFS has some of these capabilities, but last time I looked at the source, it didn't yet have journaling, which you almost need on a truly distributed file system. As a local file system, though, it ran almost twice as fast as ext2.
I havent read the Franginpani/Petal papers recently, so I can only guess - but it seems likely that it is necessary for fault-tolerance and the project uses clusters specifically to achieve higher performance as well (so the disk speed becomes less of a burden).
"I love my job, but I hate talking to people like you" (Freddie Mercury)
xFS is here (with source). An interesting project is Frangipa ni, but it is not available to the unwashed Linux masses. :-/
"I love my job, but I hate talking to people like you" (Freddie Mercury)
A bit of a (working) kludge might be to use the network block filesystem combined with the 'md' device. One box can snarf up all the network block devices (Linux to linux only) join them with 'md', and then reexport them via NFS.
This isn't terribly efficient or portable, but it might work.
-josh
I looked at a lot of distributed filesystems when working on my Master's thesis, and I still have an old page of links around at http://jab.org/thesis/thesis.html. The links page has pointers right up your ally (xFS, WebFS, etc.). Too bad about Coda not meeting your needs -- I, too, can't wait for it to become more popular.
Nice name,
Does this mean you will be using an authentication scheme like Kerbos??
Thanks for the link, I was looking at Kerbos for my network. But this looks like an option to keep an eye one.
Haakon
Last I looked, it seemed like the general consensus was that NFS sucked on Linux. It seems that FreeBSD has a much more robust and speedy implementation of it.
Not a flame, just repeating what I saw on usenet and linux-kernel.
Scuttlemonkey is a troll
Is there a URL?
-- Some things are to be believed, though not susceptible to rational proof.
Hmmm... I can't help but think you'd have more credibility if you posted something. (If you were Transmeta, you wouldn't have posted that message on /. :>)
-- Some things are to be believed, though not susceptible to rational proof.
Does anyone know of any plans to support Befs under linux?
--
grappler
Vidi, Vici, Veni
Throw all your harddrives into one file server, and turn the rest of the systems into diskless workstations..
_______
2B1ASK1
On each of the machines with the 'spare' space, make sure you can either export the partition as a file, or just create a big file that is also exported.
Then... on a single linux box, use the loopback device to turn the exported files into loop devices. Then use raid-0 to 'stripe' across all the mounted, imported loopback devices. Create your filesystem, and voila!
Don't have the resources here to try it, but it sounds like it might work.
If I were to do something like this, I think I would try to use the Network Block Device support to export raw devices onto a single host in the network. That host could then run any type of raid, or linear concatening of the individual devices, and then reexport it using NFS to the other hosts.
ftp.pc.ibm.com/pub/pccbbs/os2_ews was (and as far as i know still is) the ews repository. As of right not, i can't connect. If you search for +"tvfs" +"ews" you will probably find it mirrored somewhere.
--sean
I've never played with software raid or the network block device.. was the network block device around in the 2.0.x kernel versions? .. I doubt i'd see any performance increase- i'm sure the bottleneck is the network & the fact that things often go back and forth more than once before ending up at their destinations.
:p From my brief look at intermezzo, i am hopeful.
However, i've just grabbed myself a copy of intermezzo, and it looks like it might be able to do everything i wanted and more. I hope to somehow get my 240 disc cdrom changer into the mix so it appears as a single drive instead of 2 drives and a serially controlable robot.
--sean
I have the same problem. I've got 5 boxes running linux & os/2, and want all the "spare" space to transparently appear as a single volume on all boxes. I couldn't find anything that would do this effectivly for me, so i brewed my own. Unfortunatly (for most of you) this requires an os/2 box.
/s1/ a 6.4gig scsi drive on a linux system
Here's the details:
1) all the boxes export their spare space as nfs mounts.
2) a nifty IFS (installable file system) from IBM's EWS (employee-written software) program called Toronto Virtual File System is installed on one of the os2 boxes (we'll call this box os2tvfs)
3) os2tvfs mounts all the exported drives
4) with tvfs, all the mounted NFS drives are mounted into a tvfs drive (z: in my setup)
5) os2tvfs exports z:
6) any box that wants to access the big-virtual-volume mounts os2tvfs:/z:/
So how's it work? Lets go through an example:
box1 exports d:\, a 10 gig ide drive on an os2 system
d:\ contains a bunch of stuff, for this example we'll focus on "d:\mp3s\foo.mp3"
box2 exports
box2 has a file on it located at "/s1/mp3s/bar.mp3"
box1 then mounts os2tvfs:/z:/ as v:\
on box1, a directory listing of v:\mp3s\ contains both foo.mp3 and bar.mp3. if i copy baz.mp3 to v:\mp3s, it ends up as box2:/s1/mp3s/baz.mp3, as long as their is enough free space on box2:/bfi1/ for it, because i assigned a higher write priority to that volume when i mounted it with TVFS (it's a scsi drive- might as well use it up first). It shows up as os2tvfs:/z:/mp3s/baz.mp3.
Of course, this solution is kinda bad because it creates a ton of extra network traffic, but it was the only one i could find that did what i wanted.
--sean
You know how it's annoying when someone else in the same room as you has the same name, so when someone says "Bob" (for example), you both turn? Lame, right?
I don't have that problem. Nobody else is named Coda.
But why, in the name of God, do I have to share a name with a file system?
That's like naming a car model "Jim" or something. Or naming a really horrible piece of software "Bob"... =o)
(This is off-topic, I know, but it doesn't get more distracting than seeing your name pop up 50-odd times in a Slashdot discussion.)
-- I can't think of anything witty to put here. Sorry.
You run into some severe problems with NIS+ and NFS. Don't use them if you can get away with it. To wit:
Linux's NFS still has problems. If you need NFS use BSD (BTW, before someone mods me down for that comment, I use linux. NFS is just not a good idea in general).
NIS is a nice idea, poorly implemented, with a lot of problems with security.
You said that there was a problem w/ CODA, and that would be what I normally use rather then NFS. There are a lot of good suggestions posted here.
For distributing information ala NIS, try taking a look at LDAP instead. I have been implementing it at a few client sites, and it works much better then NIS. (There are plugins that let GLIBC and PAM use LDAP transparently, and you can even emulate NIS).
I would definitly kill for something that could transparently create a single large namespace/disk space over a network, but with disk space so cheap, you are probibly better off going and buying a 16gb IDE drive. cheep cheep....
How about exporting your available partitions as network block devices, mounting them on one of your machines, putting software RAID-0 on them and creating your filesystem on the resulting device.
I haven't tried any of this, so it may very well be crazy.
The previous post is _not_ offtopic! It's just, er, sparse.
Moderators sometimes suck.
I hope we won't have to wait as long as with Transmeta before seing the first alpha release
You could also find a cool website like the Transmeta one (which is one of the few website I have viewed in totality).
"The obvious mathematical breakthrough would be development of an easy way to factor large prime numbers." Bill Gates,
I once got Coda up & running, even over a modem.
Something I'm not sure about, though: I know that with NFS, everything stays on the server and is dished-up for all to see.
However, the impression I got with Coda was that you have a server into which you put clients, all of whom are saying 'I've got this share available'. So the file stays on the client, and other clients' requests go via the server to the client.
Is this a right understanding of the model?
~Tim
--
Rushing on down to the circle of the turn
I think he is looking for something that combines the disk space into one filesystem. NFS might bring it into one tree, but it would be a bunch of directories. YOu would have to watch how much you used in each directory. One directory will fill and another will have tons of space.
If I recall correctly, there is no problem with having patented code GPLed - so long as the license to use the patent is free. To quote the GPL's Preamble (from Version 2):
Also, the if you GPL your code, it is still copyrighted - you wrote the code, no-one can take that credit away from you (legally). What "copyleft" actually means is a clever use of copyright laws to allow everyone to use the code for free, and keep it free, as opposed to the traditional restrictions usually applied.
I recommend reading the GPL, or at least the Preamble, anyway. You could also read the GNU Manifesto. They explain these issues much more clearly than I do.
It caches at the file block level instead of at the file level (like coda), so it's not (as) affected by things like tailing a large file. It has some other feature which could be good or bad (redundancy, file block migration, etc.) depending on your particular application.
The downside? It only runs on windows, and I suspect that they keep their cache coherence and access protocols under fairly heavy wrap. Now, if someone could come up with a good argument for how they could make money developing a similar product for Linux/*BSD... *drool*. Their basic technology is applicable most places, but their implementation right now is as a Windows disk driver device.
www.mango.com
What Windows calls "DFS" is a joke to anyone who has any experience with real Distributed File Systems. They're just kludges on top of an old-fashioned network file system - a term with its own precise taxonomic meaning, not necessarily referring to Sun's presumptuously-named instance of that class - much like adding automount and NIS to Sun's NFS.
Slashdot - News for Herds. Stuff that Splatters.
>Just because you didn't succeed...
I don't usually respond to such petty comments, but I can't resist pointing out that I didn't mention what I'm working on now. I don't believe in peddling vapor.
Slashdot - News for Herds. Stuff that Splatters.
Say no more, say no more.
Your answers to my earlier questions actually lead me to believe that yours is a relatively easy case. I can see three ways to go:
Slashdot - News for Herds. Stuff that Splatters.
>but is already faster than Ext2fs, and way ahead of XFS and NTFS.
By what measures and for what workloads? Such claims are meaningless without describing the environment, and are the realm of marketroids (particularly the MS kind) not scientists or engineers.
I find it most odd that you would tout the system's distributed nature and then compare it only against local FSes. How well does it perform in sharing situations, either locally or through slow WAN links? What level of coherency does it guarantee? How is failure recovery (a very tricky issue for a DFS) handled? How about disconnected operation?
To be perfectly blunt, the lack of even an attempt to address these sorts of crucial issues makes me wonder whether the part about Charon being distributed is "part of the plan" that hasn't actually been implemented (or even designed) yet. The DFS literature is littered with papers about systems that would supposedly blow everything else away, but that never actually got implemented. I've been there, I've done that, and the sad truth is that the realities of implementing a usable DFS - i.e. one that isn't pathologically ill-behaved in at least one of the areas alluded to above - generally shred naive ideals of superfast coolness.
>Only changed disk blocks and metadata are replicated, as opposed to entire files (and only on close)
If this is really what you meant to say, it's great performance but has dire implications for recoverability. This only strengthens my suspicion that you haven't really climbed into the mud pit in earnest yet.
Slashdot - News for Herds. Stuff that Splatters.
I'm also curious what you found lacking in GFS. I have my own different ideas about "how things should be done" but perhaps explaining why you consider it inappropriate will shed some light on your needs.
As far as practical advice goes, I think most of the relevant products and approaches have been mentioned; I don't promise to have secret knowledge of any "magic bullets". DFS technology is an area where I feel we're still looking for the right answers (sometimes even the right questions). That's why I enjoy working on DFSes, but it does mean that there's a large element of "choose your poison" in evaluating current offerings.
Slashdot - News for Herds. Stuff that Splatters.
ok... but if you need betatesters, drop me a line
This is something I've been thinking about for a while. I might give a go once my current project (the user-mode kernel port) settles down.
This my current thinking on cfs (cluster fs)
All members of the cluster share a filesystem, which potentially uses all the available storage on the cluster (although you might want to keep stuff like your home directory on a separate device that you don't share with the cluster).
Files are duplicated on multiple machines for speed and redundancy. Files will tend to be located on the machines that are accessing them, so most I/O is local.
cfs will just be the networking part. Local storage will be handled by a local fs (like ext2). cfs metadata will be stored in local files with funky names (which are made invisible by cfs anyway)
There are multiple levels of membership in a cluster. Primary members can read and write everything. Secondary members can only read. They can have read copies of files locally, but they can't hand those out to other machines. Machines wanting to read a file have to go to a primary member for a copy. This is for sysadmins who don't necessarily trust their users to prevent them from becoming root and modifying files (like /etc/passwd) behind the back of cfs and then handing the new /etc/passwd out to everybody else.
Machines can be members of multiple clusters. /etc might come from a cluster that everyone is a member of, /bin might come from a cluster of machines of the architecture, /projects might come from a third cluster, etc.
Files can be marked "local" which means that they permanently live on that machine, override whatever file comes from the cluster, and aren't shared with the cluster. This would be useful for config files which are only relevant to your machine, or your email directory.
A machine's /dev would mapped into the cluster filesystem as /dev/aa.bb.cc.dd/ rather than being marked local. This gives transparent access to every device in the cluster.
A machine which a writing a file is designated the file's owner. While writes are in progress, all reads have to go to that machine. Once the writes have stopped, the machine remains the owner, but it can start spreading the new data around the cluster. It can also designate secondary owners, who would come into play if the primary owner crashes. One of them would become the new owner. If it turns out that the old owner had changes which it didn't manage to propagate and the new owner made changes, then my current thinking is that this is brought to the attention of a human, who straightens things out. If this is not acceptable for a particular file for some reason, then that file can be marked in such a way that accesses to it hang or fail until the owner comes back.
wouldnt tcfs or cfs running over nfs with multiple mounts on a single box (which could then be re-exported) do it ? Of course its not a distributed filesystem, but it should simulate one without the large cache problem of coda but with decent security.
why are you patenting it ? If its GPLed no one can claim a patent anyway (prior art). Also has linus accepted it ? Without that your are condemmed into staying in the domain of continous upgrade patches which means you either struggle to keep ahead of the kernel or you become obsolete. and what do you mean by copyrighted ? GPLed code can never be copyrighted only copylefted.
- NIS -- share various maps, in your context most notably NFS maps so every machine knows where every export is on every machine
- automount/autofs -- on demand mounting of various shares
- NFS -- obviously, for the various exports
Two caveats:*** Proven iconoclast, aspiring bohemian. ***
> why are you patenting it ? If its GPLed no one
> can claim a patent anyway (prior art). Also has
> linus accepted it ? Without that your are
> condemmed into staying in the domain of
> continous upgrade patches which means you either
> struggle to keep ahead of the kernel or you
> become obsolete. and what do you mean by
> copyrighted ? GPLed code can never be
> copyrighted only copylefted
First, you don't know that someone is stealling your prior art until after they already have a patent. At which point it is virtually too late, since getting patents over turned is extremely hard.
Second, they said they were planning this too be a cross platform file system, which means that whether or not Linus officially supports it isn't going to kill the project any more than the head of Sun officially not supporting it will. Second, Linus will probably accept it if it is good. From the sounds of the project, it is too early for him to either have accepted it or rejected it.
And finally, GPLed code can very much be copyrighted. Legally, copylefted is not recognized other than as type of license to copyrighted material. Without copyrights, there is no GPL, only public domain. In fact, it is copyrights that make GPL binding and effective.
Actually, by default any item you create is legally copyrighted. If I remember correctly, if you don't mark any copyright on it, then the best you can hope for in the case of theft is a cease and desist. If you mark it copyrighted, you can collect damages up to a certain limit (damages meaning that you can collect any earnings made directly from your work), and if you register that copyright, you can then collect punitive damages.
-- Superlame http://catpro.dragonfire.net/joshua/
The comparisons to local filesystems are appropriate. Charon is designed to operate not only as a distributed filesystem, but also as a totally local filesystem without any other computers being involved.
We'll post full benchmark results when we're ready, along with the methodologies, hardware and source code used.
>This only strengthens my suspicion that you haven't really climbed into the mud pit in earnest yet
Patience. Just because you didn't succeed...
Napster-to-go says "Fill and refill your compatible MP3 player", which is a lie. It's not MP3. It's WMA with DRM.
Not yet. We want to release the filesystem when we're ready -- i.e., when more of the code and docomentation are done.
:) -M
Pretend we're transmeta for the time being...
Napster-to-go says "Fill and refill your compatible MP3 player", which is a lie. It's not MP3. It's WMA with DRM.
He's the guy who takes the dead across the river styx.
You *can* patent, copyright and GPL all at once, BTW. As an example, look at the SQUID license (for copyright+GPL):
I don't know of anything that's been both patented and GPLd, but CAST encryption is close. Its creators patented it, but made it available for all uses, anywhere, for free. That keeps someone else (not going to mention any specific companies or professions here) from attempting to patent it later, pre-empting any stupid legal battles. We're doing the same thing.
We've not approached Linus for his blessing. It's a little early for that. Don't look for it in the 2.4 kernel.
Napster-to-go says "Fill and refill your compatible MP3 player", which is a lie. It's not MP3. It's WMA with DRM.
I dislike letting the cat out of the bag this early, but those of you who pay attention to linux kernel-development lists already know some of this.
We're writing a new distributed filesystem called Charon. It will be patented ("patent pending"), copyrighted, and GPLed. It's a true 64-bit, journaled filesystem that supports exabyte-plus file and volume sizes, sophisticated access control lists, per-directory quotas, distributed zero-knowledge protocol authentication, encryption, replication, named streams and indices (see BeFS, ReiserFS -- although we don't use B-trees of any type). It's in alpha stage right now, and full of debug code, but is already faster than Ext2fs, and way ahead of XFS and NTFS. We will be porting it to Solaris and NT after development on Linux is complete.
Unlike Coda, AFS, DFS, etc. replication, every Charon server is a full read-write replicant. Only changed disk blocks and metadata are replicated, as opposed to entire files (and only on close) as in Coda. Charon clients are partial replicants -- they use the local file system as cache and rely on their home server(s) for token management and authentication. The system also supports heirachical failover and replication.
Because of the way it is designed, it also supports a very nice feature for GUIs and web servers -- a very fast built-in file types database that provides a single repository for mime type, friendly name, icon(s), description, extension, and other information. Sort of alike the Windows registry, but much less stupid and much higher-performance.
Stay tuned! This isn't vaporware.
Napster-to-go says "Fill and refill your compatible MP3 player", which is a lie. It's not MP3. It's WMA with DRM.
My school, UMBC (Univ MD, Baltimore County) has a linux box that somehow is using AFS in thier irix cluster.
Hope that helps!?
Peter Braam's contribution was that he ported Coda to Linux (it originally ran on BSDi or NetBSD; I forget which). This was a lot of work but FAR less than Kistler's contribution.
A buddy of mine (John Carter, professor at the University of Utah) was the chief architect/programmer of Mango's Medley (www.mango.com). It would be ideal. It lets you take spare space on a bunch of Win machines and use them as a virtual fileserver. The really cool thing is that is does transparent mirroring, plus if you're using a file it automatically turns your box into one of the mirrors so that it will be even faster than the fastest file server. And the company has a really cool name ;-)
Problems:
(1) It has only been written for Windows. But not that hard to port.
(2) More serious: they initially did it on Windows because that's where they saw a larger potential customer base. But my friend, last we spoke, said that despite the practicality of the product (and winning best of show 2 or 3 years ago at Comdex) they still haven't had any substantial sales. So a port isn't likely to happen. The best would be if they opened up the source for Linux (they still have a patent on the Windows version, so it probably wouldn't be a problem), but I have no clue if they would ever consider that. Regardless, somebody needs to write such a system for Linux/BSD. Probably wouldn't even be that hard.
An OS that may suit your needs is inferno by Lucent. It is designed to be cross platform and allows ditributed resources. It works on Linux, Wintel, SPARCS, etc. It is remarkably small, as it was designed for embedded devices to be able to have a common ground with different platforms and OS's.
How will this filesystem work on a switch? Will all traffic be routed through a single server port, or can the distributed data be moved through the most appropriate switch port?
--Lawrence Lessig for Congress!
The "problem" with Coda, at least from my perspective, and please follow the link in the original article for full details, is that any file accessed by a Coda client is first copied to the local workstation *in its entirety* to be worked on. That means if you need to work on a 2GB file on the file server, you'd better have 2GB of space allocated to Coda cache on your workstation. Kinda sucks.
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My mom's going to kick you in the face!
Coda *is* a blast. My favorite part is the disconnected operation. My least favorite part is the local caching. If you want to copy a 2GB file to your local machine, that means you need 2GB of free space to hold the file *plus* 2GB of free space to hold the locally-cached copy.
I guess for an essentially academic project it's kinda cool, and for other situations -- like as the back-end for a cluster of web servers -- it would work really well, but for me, where I *am* reading/writing big files around a lot, that part of it really sucks.
-=-=-=-=-
-=-=-=-=-
My mom's going to kick you in the face!
If you haven't registered your copyright, you can still claim actual damages, which basically amount to whatever profits the infringing entity made off of your copyright. What you don't get are the punitive damages, which can be up to $100,000 (plus legal fees, etc).
/.'ers and GPL'ers don't realize this.
The second point I'd like to clarify, which superlame touched on briefly, is that there is no such thing as copyleft as opposed to copyright. Copyleft is just a clever coinage that the FSF/GNU came up with. It is a form of copyright licensing, but it isn't an alternative to it. It is amazing how many
If there are any contradictions between copyleft and copyright, copyright is going to win. There are several elements of the GPL which haven't been legally tested and if the courts don't interprete copyright law the exact same as the FSF/GNU, it is very possible the GPL could be ruled invalid. Being aware and understanding these issues is very important to the survival of copyleft software. Just because RMS says something works this way doesn't mean it does.
Please, don't assume. If this is an issue that affects you (e.g. you are authoring code), please read both the GPL and copyright law.
n8_f