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Distributed Filesystems for Linux?
Zoneball looked at 3 distributed filesystems, here are his thoughts:
" Open AFS was the solution I chose because I have the experience with it from college. For performance, AFS was built with an intelligent client-side cache, but did not support network disconnects nicely. But there are other alternatives out there.
Coda appears to be a research fork from an earlier version of AFS. Coda supports disconnected operations. But, the consensus on the Usenet (when I looked into filesystems a while ago) was that Coda was still too 'experimental.'
Intermezzo looks like it was started with the lessons learned from Coda, but (again from Usenet) people have said that it is still too unstable and it crashes their servers. The last 'news' on their site is dated almost a year ago, so I don't even know if it's being developed or not"
So if you were to recommend a distributed filesystem for Linux machines, would you choose one of the three filesystems listed here, or something else entirely?
NFS Linux FAQ
Howto #1
Howto #2
If you find yourself needing help, try asking people at Just Linux forums, or trying the NFS mailing list.
NFS + Automounter plus NIS and you get everything you ever wanted. NFS is fast, well known and documented and transparent.
I would use SFS, the Self Certifying File System. Assuming all the systems you are using are supported, it offers global, secure access to anything you care to export.
Since openafs forked from the old transarc/IBM codebase, it looks as if it has a real future. It's used by a load of educational and research institutions (notably CERN), as well as Wall Street firms.
I'm sure other ehere will suggest NFS but why not just go whole hog and setup you clients to boot off a server then mount the same NFS filesystem. That way total transparency without having to make sure that n FS is always mounted
Just my $00.2
Rus
Cheap UK and US VPS
Check here for a good background on DFS. It also has a quick table comparison of the popular programs, and a walkthrough to set up Intermezzo.
We use PVFS at work to give us a high-performance network filesystem for use with our clusters.
http://parlweb.parl.clemson.edu/pvfs/
I run an openmosix cluster with the openmosix filesystem here at work. Three computers.. no problems...
If you want to take a look..
http://lucifer.intercosmos.net/index.php
linkage and I am going to be placing some tutorials up. -joeldg
anime+manga together at last.. in real time.
DFS is just replication. DFS works in a number of ways in simplest form you could use rsync to achieve the same thing. Combination of NFS and RSYNC could be used to achieve its more complex form.
Samba works fine. I personally have approximately 5 samba mounts in my filesystem totally transparent for anybody who was to walk up and use my computer.
No need to unnecessarily complicate things here, samba is simple to set up and functions great.
That's what NIS is for. You can schedule regular downloads of group/passwd files, which are updated in a NIS database stored on a master server, and passed down to "slave" servers.
While there is no new news posted on the site, ther are current tarballs on the ftp server, as recent as 5.9.03. (but that file appears to be a redux, last update to code seems to be 3.13.03)
The sourceforge page for the project (http://sourceforge.net/projects/intermezzo) shows status as production/stable but the info there looks stale too.
This guy must have installed too many versions of the same Microsoft products. ... You can still configure you networking using scripts for 2.0- or 2.2-based distros. You can often use 20 year old programs under Unix, albeit sometimes with some effort.
In the GNU/Linux world, BSD world, and to some extend in the entire Unix world, good designs do not become obsolete. Even not-so-good designs often stick around, for the sake of backward compatibility. In the newest greatest Linux kernel, you can still have a.out support, NFS, Minix, FAT16 filesystem support
Only in the M$ world is obsolescence such a big issue, because that obsolescence is planned. In short, don't worry that much about obsolescence : if Coda is as good as it looks, it'll be there for a long time. If SomeCrappyDistributedFS FileSystem is used by enough users, it'll stay around for compatibility's sake anyway, even if it sucks.
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
To be honest, big time, but a lot of people forget the other side of life with NFS, and that's NIS/NIS+. The yp-tools include pretty good NIS support, but not sure of NIS+. Would use niether in a production environment personally, but a common Auth system which is easy to manage would solve that issue.
/home directory of 5 computers onto / on a central system and it display all the mounts simultaneously. For example:
/home/foo
/home/baz
/home/tic
/home/tac
/home/toe
/home /home /home
/tac
/toe
/foo
/baz
Could also look into LDAP (VERY complex, no good starting point that I've been able to find) and Kerbreos auth methods as well.
Should give you a central point for uids/usernames. But NFS does not have transparent mounting that I'm aware of so that you could mount, say the
<ECODE>
CPU1 contains:
CPU2 contains:
CPU3 contains:
on CPU4, you'd do the following:
mount CPU1:/home
mount CPU2:/home
mount CPU3:/home
And you'd end up with on CPU4:
/home/tic
</ECODE>
If there is a way to do this, please lemme know. I've heard people talk about it in the past, but haven't seen anything come of it yet.
-What have you contributed lately?
That should have read...
Format, Install Windows Server 2000 or 2003, Repeat
What you are looking for is 'autofs', which has been used extensively in solaris and linux for years (forever). You can set up an NFS share and then have autofs mount/unmount it on demand. The advantage is that if the share is not in use it's unmounted and the machine will be less vulnerable to hanging if the NFS server goes down. See the AutoFS Howto for more information on setting it up.
-- Greg
Slashdot, would a spell-checker for posting be too much to ask? It's not rocket science!
It seems like a distributed filesystem might be overkill for your needs. If what you really want is the appearance of a single common machine, why not just pick one as a server, and set up your other boxes as X clients. You can even pull out most of their memory and storage, and stick it in the server, thus turning them all into pretty powerful machines.
Money I owe, money-iy-ay
Just so you all know. NFS is a network accessible FS. A DFS can also be network accessible from clients, but it physically resides on multiple systems.
Whoa, you definitely need Unison.
Unison will synchronize any two file trees in The Right Way (TM).
Get the gtk version for interactive conflict resolution.
((lambda (x) (x x)) (lambda (x) (x x))) http://www.endpointcomputing.com a scientific approach to custom computing.
Slashdot, would a spell-checker for posting be too much to ask? It's not rocket science!
Which offers the best stability and protection from future obsolescence?
The best protection from future obsolescence is to use something that is already obsolete.
I usually use rsync for one way backups, and unison where I need 2 way synchronization.
Rsync is nice because you can update lots of files very quickly, as it only moves binary diff's between files. Also, if it is a costly network link, you have the option to specify max transfer rates, so you don't kill your pipe when it runs from your cron job.
Unison is nice because it is pretty smart about determining which files should be moved, and can correctly handle new and deleted files on either end of the link. Plus it supports doing all of it's comm via ssh, so it's secure.
rsync
unison
The downside to both of these being that neither of them are instantaneous. However, I've had much success running both of these as often as every 5 minutes. Just make sure that you launch them from a script that is smart enough to check for already running instances before it starts trying to move data.
It's become such a part of my day to day life that I can't really describe the things I was missing before. The best things about it are probably the strong, flexible security and ease of administration. It also gives you everything you need from a small shop all the way up to a globally available decentralized data store.
There seems to be a good comparison here. I would strongly recommend AFS for all of your distributed filesystem needs. (The OpenAFS developers are cool too!)
LRC, the best-read libertarian site on the web
I just went through this process a few weeks ago and I must say I'm really glad I went through the trouble of setting it up...it's very cool. I actually wrote a tutorial about how to accomplish this by using NIS and NFS. I hope you find it helpful.
The only trouble you might run into with the setup I used is some file-locking issues with programs wanting to share the same preference files.
--It's Pimptastic!--
And here I thought you were going for "+5 funny". rsync as a DFS? Man, that's scary. Someone get this guy a job at Microsoft!
The problem with these distributed files systems seems to be that they're either pretty old and lacking features like disconnected operation (AFS) or seem to be unstable or, even worse, unmaintained (Intermezzo, Coda).
For many simple purposes backups can be done quite nicely using rsync or something like bacular. For laptop/notebook support unison is definitely worth a look. It syncs directories like rsync does, but in both directions. Works nicely for me.
time is a funny concept
Anyone with a desktop and a laptop they want to maintain in sync definetely needs Unison. This is one of the coolest tools I found after I picked up a laptop.
I've spent quite some time researching this issue for here at work. We have two primary offices, separated by a 256k of network topology. Too slow for most users to find acceptable (large files, several 10s of seconds to copy). A bit of a culture problem but oh well.
k it/samplechapters/dsdh/dsdh_frs_tkae.asp
I looked into a whole pile of options for having a "live" filesystem, a-la NFS, but the bandwidth killed interactivity (this is for users who've never used 100mbit network filesystems before).
I found the following:
1. Windows 2000 Server includes a thing called "File Replication Service". Basically, it's a synchronisation service. You replicate the content to many servers, and the service watches transactions on the filesystem, and replicates them to the rest of the mirrors as soon as it can. You can write to all mirrors, but I never quite worked out how it handled conflict resolution.
A chapter from the Windows 2000 Resource kit that describes how it works: http://www.microsoft.com/windows2000/techinfo/res
2. Some people have done similar work for Unix systems, but they mostly involve kernel tweaks to capture filesystem events. Can't remember any URLS, but some Googling should find it.
3. Some people are using Unison to support multi-write file replication. So long as you sync regularly, you shouldn't have too many problems.
4. The multi-write problem is a hard one, so most people tend to say "don't do it, just make the bandwidth enough". This is the way to go if bandwidth isn't an issue.
A guy by the name of Yasushi Saito has done quite a bit of research into data replication. Some papers (search for them on google in quotes). He also put together a project called "Pangaea" which tries to do as described above. It wasn't great last time I looked. Some paper titles:
- Optimistic Replication for Internet Data Services
- Consistency Management in Optimistic Replication Algorithms
- Pangaea: a symbiotic wide-area file system
- Taming aggressive replication in the Pangaea wide-area file system
There is also a bunch of other research work:
- Studying Dynamic Grid Optimisation Algorithms for File Replication
- Challenges Involved in Multimaster Replication (note: this talks about Oracle database replication)
- Chapter 18 of the Windows 2000 Server manual describes the File Replication Service in detail
- How to avoid directory service headaches (talks about not having multi-master-write replication and why)
That's like saying "jumping off a cliff is not the most intelligent thing to do." NFS is easily the LEAST secure option of ANY filesharing system.
NFS is only appropriate on a 100% secured(physical and network-level) network. If anyone/someone can plug in, forget it. If anyone has root on ANY system or there are ANY non-unix systems, forget it. If ANY system is physically accessible and can be booted off, say, a CDROM, forget it. The only major security tool at your disposal is access by IP, which is pathetic. Oh, and you can block root access.
Even though you can block root access for some/all clients, it's still massively insecure, and this remains NFS's greatest problem. You have zero way of authenticating a system. NFS is like a store where you could walk in, pick up any item you wanted, and say "I'm Joe Shmoe, bill me for this!" and they'd say "Right-o!" without even looking at you. All systems with the right IPs are explicitly trusted, and their user/permissions setups are also explicitly trusted.
NFS is a pretty good performer, especially when tuned right and on a non-broken client(which linux is VERY far from.) However, its entire security model is in dire need of a complete overhaul. There needs to be a way to authenticate hosts, for one, more similar to WinNT's domain setup, which is actually incredibly intelligent(aside from the weak LANMAN encryption.) The administrative functionality in NFS can't compare to the features that have been available to MacOS and Windows administrators for over a decade, and it's purely embarassing.
Either that, or AFS/Coda need to get a lot more documentation and (for Coda)implementation fixes. The unix world desperately needs a good filesharing system...
Please help metamoderate.
Other options like LDAPS and Kerberos offer at least some form of security.
ypcat, then brute force attack on the resulting passwd file is as old as dirt, and sadly still works. I was a bit dissappointed when I saw NIS as a required service on the Redhat cert syllabus.
This may sound harsh, but I don't think there is much excuse for run NIS in this day and age. Anyone who does this in an environment where security is a concerns deserves what they get.
Based on upvotes, Ageism is the only "-ism" Slashdotters care about and think isn't SJW
I had more or less the same basic requirements and I opted for AFS.
:DFS, DCOM, Directory Services, SSO, DCE-RPC, etc.)
My needs were a little more demanding (had to be implemented in GNU/Linux, Solaris, AIX, HP-UX and as an extra Windows 2000) and grocking AFS can be difficult at first but it was the best choice by far. Stable across all the Unices, very secure (this was another requirement) and integrates perfectly with our Kerberos Domain and LDAP accounting info. It provides a unique namespace that can span multiple servers transparently, does replication, automatic backups and read-only copies, client-side cache with callbacks, has a backup (to tape) system that can be used stand-alone or integrated with existing backup structures (Amanda, Legato, TSM) AND was the basis for the DCE filesystem, DFS (as a side note I find it interesting - and sad - that most things people try to emulate this days are present in DCE , and Windows 2000 got many of the "new features" from a technology initially made for Unix
AFS is amazing and much more robust than any distributed filesystem I know of; it has shortcomings when servers time out, but apart from that it's really an excellent solution; an example I generally use to give an idea of some of the good features of AFS is a relocation of a home directory to another server. The user doesn't even notice that his home directory was moved to another server *even if he was using it and was writing stuff to disk*; at most all writing calls to his home dir have a small delay (a couple of seconds) even if his/her home dir was 5 Gb worth.
Kerberos integration is an added bonus, if you can you can use this as an excuse to kerberize your systems and form a Kerberos Domain. If you don't want to just stick with the standard AFS KA server.
In my setup I have Windows users accessing their home dirs in AFS using the Kerberos tickets they have from the Windows login and the fact that a cross-realm trust was made between the Unix DOmain and the AD; the can edit all the files they are entitled to with that ticket, and the system is so secure that Transarc used to put the source code in it's public AFS share and added the customers that bought the source to the ACL of the directory that contained it.
With all this features it would be hard not to vivedly recommend OpenAFS as the best solution for a unified, distributed filesystem. Bandwidth utilization is, in my experience, at least half of what NFS uses, which is an added bonus.
cheers,
fsmunoz
It's been featured on slashdot before.
Non-Linux Penguins ?
rsync -e ssh -azu --bwlimit=500 --stats --exclude='/proc' --exclude='/dev' / targetsystem:/targetdir/
-e is how to go - so -e ssh means use ssh
-a (archive mode - see docs)
-z compression - if you have more CPU vs pipe, use it. but if you are on a lan, you probably want to leave it off unless you don't mind the cpu hog (fat pipes will use more cpu time for compression)
-u update only (dont overwrite newer files)
--stats show you what it did when it is done
--exclude leave off paths/files you want to skip
--bwlimit in KBps - from my exp, put half of what you want your max to be.
Ryan
I think you should clarify what you mean by "distributed"... becuase that word is going to cause a lot of confusion.
IF you want a few linux boxes to all basically share a lot of files, so you can log into any one, do whatever, only install stuff once... nfs is fine. If it's just on a private network just for you.
NFS is not considered a "distributed" filesystem... but I'm not sure that's what yo want anyway.
We use NFS every day, but just for very special circumstances. If you really understand how NFS works, then you will understand why NFS is just not a viable solution for anything large scale, or small scale for that matter.
:)
NFS is not secure. At most sites, NFS is exported read-only and limited to the domain, or to a given set of machine(s). If you export NFS as read/write then the client had better be secured, or you better use kerberos, and for damn sure better be behind a firewall. NFS has no client side cache, no volume location service, no ACL's, no authentication (unless kerberized), no replication, yata, yata, yata. We've used NFS sparingly for over 15 years because we -know how it works, and know its limitations.
On the other hand, we set an AFS cell for enterprise scale application and data sharing. It currently uses Kerberos V authentication, has volume replication, global namespace, client cache, fault tolerance. User's can setup their own groups, set their own ACL permissions. Did I say quota? AFS has per-user/per-volume quota. Hey, guess what, symbolic links work from any volume to any volume on AFS. And, AFS is just a simple daemon. You crank it up, mount the top of your cell and poof, you are done.
Another positive is the fact that once you setup an AFS cell you automatically become part of a larger community. Any AFS cell can mount the entire file system of another AFS cell within the same tree. I can for example mount many large university and government cells and share files. AFS allows Internet-wide file sharing with full security. On most versions of the client you can even enable encryption on the connection so your files won't be snooped easily.
All of our Solaris, Windows, Linux, and Mac boxes can use the same AFS tree without blinking an eye. We use AFS for many things. Before LDAP was really worth anything, we used AFS for simply exchanging read-only data. It -is- a replcated and global file system! Just put your config files in the tree and you are done.
If you are one of those people who are blinded by "always doing things one way", then I'd suggest you wake up and smell another technology, I did, and I liked what I got in return. Look into OpenAFS, you'll be glad you did.
+10,000 karma points!
I'm vaguely sure this is a brand new affront to RMS, but I just can't put my finger on it.
... and the gaping wide security hole that is NFS.
... thanks ... my accounting data now!".
... about 15 years ago.
"Hello, I'm user ID 500 and I'd like my home directoy
NFS doesn't actually have security anymore, never has since IP-capable machines became physically portable but more importantly since the assumption that every box would have a trusted admin became invalid
KILL NFS, we need something that doesn't suck.
Why not stick with NFS for the time being?
I went through the "is coda right for me?" phase, and also "is intermezzo right for me?" and also spent tens of hours researching distributed filesystems and cluster filesystems online ... my conclusion
is that the area is still immature, I will let the pot simmer for a
few more years (hopefully not many), and use NFS in the meantime.
My situation: desire for scalable and fault-tolerant distributed filesystem for home use with minimal maintenance or balancing effort. Emphasis on scalable, I want to be able to grow the filesystem essentially without limit. I also don't want to spend much time moving data between partitions. And last but not least, the bigger the filesystem grows, the less able I will be to back it up properly. I want redundancy so that if a disk dies the data is mirrored onto another disk, or if a server dies then the clients can continue to access the filesystem through another server.
All that seems to be quite a tall order. I checked out coda, afs, PVCS, sgi's xfs, frangipani, petal, nfs, intermezzo, berkeley's xfs, jfs, Sistina's gfs and some project Microsoft is doing to build a serverless filesystem based on a no-trust paradigm (that's quite unusual for Microsoft!).
Berkeley's xFS (now.cs.berkeley.edu) sounded the most promising but it appears to be a defunct project, as their website has been dead ever since I learned of it, and I expect the team never took it beyond the "research" stage into "let's GPL this and transform it into a robust production environment". Frangipani sounds interesting also, and maybe a little more alive than xFS.
On the other hand coda, afs and intermezzo are all in active development. afs IMHO suffered from kerberitis, i.e. once you start using kerberos it invades everything and it has lots of problems (which I read about on the openAFS list every day). AFS doesn't support live replication (replication is done in a batch sense) either.
CODA doesn't scale and doesn't have expected filesystem functionality: for 80 gigs of server space I would require 3.2 gigs of virtual memory, and there's a limit to the size of a CODA directory (256k) which isn't seen in ordinary filesystems. There's also the full-file-download "feature". CODA is good for serving small filesystems to frequently disconnected clients but it is not good for serving the gigabyte AVIs which I want to share with my family.
Intermezzo is a lot more lightweight than CODA and will scale a lot better, but it's still a mirroring system rather than a network filesystem. I might use that to mirror my remote server where I just want to keep the data replicated and have write access on both the server and the client, but it's again not a solution for my situation.
The best thing about intermezzo is that it sits on top of a regular filesystem, so if you lose intermezzo the data is still safe in the underlying filesystem. CODA creates its own filesystem within files on a regular filesystem, and if you lose CODA then the data is trapped.
Frangipani is based on sharing data blocks, so like NFS it should be suitable for distributing files of arbitrary size. I need to look at it in a lot more detail; this is probably the right way to build a cluster filesystem for the long haul. For the short term, Intermezzo is probably the right way for a lot of people: it copies files from place to place on top of existing filesystems.
What I did in the end:
The way it works is tha
Samba DOES support UNIX permissions. Use the "cifs" client module not the "smbfs" one, and enable UNIX extensions on smbd. Its not hard, and works well.
That said, I haven't tried it in real production yet. I do find it scary that a reverse-engineered MS protocol is now an option for UNIX<->UNIX network file access because NFS is so obsolete and crap that anything looks good in comparison.
Um.. Linix? Learn the name of your fucking operating system, to start off with. It's spelled L-U-N-I-X.
In the medium term, however, I think WebDAV will become a better option, because it can be served and accessed with standard web servers and clients, in addition to being mappable onto the file system.
The Linux kernel already has WebDAV support (CODA hooks plus some user-mode process), although I'm not sure how well it works.
But for a lot of applications, you simply don't need that much, and you've got some way to contain the security risks, and NFS can be enough. It's easy enough to set up, and if all you're *really* trying to do is make sure that everybody sees their home directory as /home/~user, and sees the operating system in the usual places and the couple of important project directories as /projecta and /projectb, NFS with an automounter and a bunch of symlinks for your home directories is really just fine. They hide the fact that users ~aaron through ~azimuth are on boxa and ~beowulf through ~czucky are on boxbc etc. And yes, there are times you really want more than that, and letting your users go log onto the boxes where their disk drives really are to run their big Makes can be critical help. But for a lot of day-to-day applications, it really doesn't matter so much.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
Watch for the new version of NFSv4. There are already a sample implementation in the linux 2.5 tree. NFSv4 will address most of the problems that NFSv3 and others have. Including plugin security models, namespace, and revamped ACL handling.
It's also WAN friendly, letting several operations be done at the same time with a single directive. (COMPOUND directive) It also allows you to migrate one filesystem to another with no stale filehandles. Basically, it's trying to be an AFS killer.
For more information, take a look at
http://www.nfsv4.org/
Lots of good info including the IETF spec. It's a interesting read.
The spec is not quite complete. Currently, I believe there are discussions with how NFSv4 will work with IPsec.
Cheers,
sri
I've been partial to GPFS (general parallel files system) on AIX, IBM's also got a version for Linux...Probably RH specific. There's also JFS, works alright...a bit more development there would be a plus. GPFS works great on Linux clusters!
To do a true backup, you must copy permissions. To copy permissions, the target system needs to have the same UIDs and GIDs as the source system. This is hard to do on Windows and OS X. Typical tools such as rsync, Unison and rdiff-backup make no effort to solve this problem. Suggestions?
Doesn't samba-tng support a true DFS, exporting a virtual file system (combination of shares from multiple systems)?
Anyone using it?
CVS.
It's got powerful replication services, although manually run.
Disconnected operation is no big deal with CVS.
As for distributed file systems, make one system the CVS server. Make sure all your systems "cvs update" by a cron job that runs often. If the main server explodes, your next task is to set up a new server. Set up your DNS so cvs.whatever.com points to your current CVS server, and keep a hot standby ready. Change the DNS to point to the new CVS, CVS commit from any of the slave servers that were doing "cvs update" every 5 minutes, and you're up and running again. Could automate it, if I had enough problems to make it worthwhile.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
There's some reasoning behind the lack of big interest in distributed filesystems.
1) Obviously, NFS continues to be a passable solution where you dont really need "distributed" so much as "universally network accessible in a simple way".
2) For things where you truly want "distributed" access from multiple machines that are local to each other, there's a somewhat less complicated solution, which is to use shared storage. The idea is to attach all the machines to a SAN-style network (fiber channel, or hey even firewire these days) and use a sharing-aware filesystem that allows simultaneous access to the storage/filesystem from multiple hosts with sane locking and whatnot. One of the better places to look for this is otn.oracle.com - they've released a cluster-filesystem *and* drivers for firewire shared storage (which is cheaper than fiberchannel) for linux.
Of course, that leaves out the case of a distributed filesystem for machines that can't be on a SAN together for distance or economical reasons. In that case you could of course hack something up using cluster-filesystem type of filesystem and SCSI-over-IP or something like that I guess, or use one of the experimental distributed filesystems you mention... but the market just isn't big enough for this yet to drive much.
11*43+456^2
Use rsync. Default is to map user and group names at both ends of the connection, unless you specify --numeric-ids. Of course you have to have at least the names right, otherwise there's nothing to work with. And you need rooteness on the receiving end, but that's also to be expected.
I've been using rsync for some time now to manage moving research data between home and school and I'm thoroughly impressed. Great piece of software.
Stefan Axelsson
It would be very good to remember that NFS comes from:
Not
For
Security
IBM deployed a new distributed filesystem that goes beyond AFS, it's called GPFS and it's part of the xCAT package. You can find it here.
Unfortunately, documentation is really poor at this moment... but I think it could be a really good solution.
May the source be with you!
NFS really can't stand machines being switched on and off, NFS is great in a production environment if setup correctly, but not for home usage.
MacOS X and M$ can handle SAMBA just fine (although MacOS X still can improve with handling filenames wich contain characters such as [ and ] and some other small caveats).
I know it's the M$ protocol, but Linux has the best implementation of it. It works just great!
The 'shares' of shut down machines disappear as soon as you try to access them on other machines. If you don't access them while they were off they stay in place. For ease, you can put a 'mount -a' in the crontab to automagically remount these unmounted filesystems.
It just works. 3 times 'HURRAY' for SAMBA!
I mean, if I use AFS, does that mean from now on, every time I run an install script for some random package that chmods something, I have to realize that the script doesn't really work, and then I have to analyze its intent and then do some ACL thing that accomplishes the same intent? Ugh, I am not interested in things that create more work for humans.
Another annoying-looking thing is that it's really a filesystem, even from the servers' point of view. Unlike sharing/exporting services such as NFS and Samba, which you can run on top of your choice of filesystem (ext3, Reiserfs, xfs, etc), it appears that AFS/OpenAFS combines both the disk and the network topics. That means you don't get the advantages of all the great work the filesystem geeks have been doing in the last few years.
It almost strikes me as inelegant design or something, that a single project concerns itself with both the details of how things are laid out on a disk, and also how to do network-related things such as replication. Somebody made their black box too big for my tastes.
Am I wrong about all this?
As copyright owner of this comment, I authorize everyone to defeat any technological measure which limits access to it.
I guess this doesn't really apply to "home usage" but I have to manage a lot of machines over a SAN and if you don't want people screwing up your SAN, you better use something like CXFS.
:)
CXFS uses a sort of token technique and allows multiple file accesses. That way, we get the same files on all the machines but w/o the NFS overhead and network congestion. File read/write are done over the fiber channel switch and the "metadata" is done over a private network. This is WAY much faster than NFS over Gigabit Ethernet. One good thing about CXFS is the redundency possibility. You can have failover servers and other neat things.
The only drawback, is that you need an SGI server but then, you can use Windows and Solaris clients. Very stable but probable not for home use
-- Leeeter than leet