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Merits Of The Different Journaling Filesystems?
a2800276 asks: "The story that XFS has gone beta raised some questions in my mind. There are now four journaling filesystems available under various OSS licenses and being actively developed for Linux, there being (in estimated order of maturity): SuSE/Namesys's reiserfs, SGI's XFS, IBM's JFS and Tweedie/Redhat's ext3fs. Avoiding the obvious question of why can't the effort going into four different projects be channeled into one, I think a discussion of the particular merits of the different fs's would be interesting."
Early adopters like you make me sick. I'm a FAT12 man ... once it's stable I may consider FAT16.
BeOS has the best Filesystem (not the fastest though). It's 64-bit, journaling and make use of the attributes and mime types. For more about it, click here.
This is not, properly, a function of the file system.
Instead, you want a file-monitoring daemon, independant of the many fs's you may be accessing. This will include monitoring the changes across NFS, etc., and removable-media.
SGI Irix does this beautifully with its File Alteration Monitor (FAM) and Inode Monitor (IMON).
If you've ever used the 4Dwm filemanager, you'll know what I mean.
Fortunately, SGI has added these projects to its OSS roster, and documented, portable sources are available at: http://oss.sgi.com/projects/fam/
Jeremiah Cornelius
"Flyin' in just a sweet place,
Never been known to fail..."
Isn't security built around this very thing?
Since the context of the conversation revolved around things root does, I replied in the context of someone who is root, so no.
Furthermore, as hardware moves more and more to firmware, there are bugs that can turn a machine into a boat anchor. I would very much like the OS to refuse to perform these operations.
Not me. I want it to require confirmation that I REALLY REALLY mean to turn it into a boat anchor, but if I confirm, it should DO IT. (Possably, I know something it doesn't! Like the hardware is modified or I want the disk dead for some reason).
Consider 'rm -rf /' for example, it WILL do it.
In the context of mounting a cleanly unmounted ext3 filesystem as ext2, that thing that I know and it doesn't is that I did unmount it cleanly, and from the documentation, I know that this is safe.
If you can't deal with it, you should not allow the user to use the feature at all.
That's not the Unix way. An OS should NEVER absolutely refuse to do what it's told to do (if it's possable). In this case, it IS possable. This is an especially good thing in a developmental file system. People who can't or won't follow that simple instruction shouldn't be messing with a pre-beta filesystem at all.
Your experiances and mine are quite different. The only files I've lost in a power fail situation were ones that were new and would have been suspect anyway.
Any filesystem will loose recent data if the power fails simply because there will be uncommitted buffers.
Of course, killing off kflushd and various other 'performance' tweeks can and will greatly increase the odds of loosing data.
If you want journaling, I have tried ReiserFS in production, and found it to be quite nice in versions for 2.2.x. It recovers much more quickly than an fsck.
Just remember, reiserfs still won't save you from total hardware failure due to power spikes.
smash
I run: Windows, OS X, Linux, FreeBSD. Just because you have a hammer, doesn't mean everything is a nail.
However, I believe that this limit only exists on 32-bit architectures -- perhaps there was a bug which prevented 64-bit architectures from using big files too, and that's what was fixed in 2.2.14 (or
--
The key word here is background. A defragmentation process running with a low priority that flushes its changes to disk regularly will not affect applications running at normal priority. Of course, if you're burning a CD or something, you will have the option of turning it off temporarily.
As an aside, the Indexing Service on Windows 2000 isn't bad. The original version was written by one of these people.
--
"Where, where is the town? Now, it's nothing but flowers!"
ext3 journals both data and metadata. Part of the current effort is being directed into allowing it to journal metadata only. Metadata-only journalling is useful in situations where good write performance is required, since journaled filesystems by definition write everything twice, once to the journal and then finally to the location on disk where the data belongs.
--
"Where, where is the town? Now, it's nothing but flowers!"
NeXTStep used the Unix file system and thus has no more attributes than any Unix system. They used ".app" directories, which is a good example of storing such information in a way that is easily copied to other systems, and in a way that avoids complicating the file system. Each "attribute" is a standard file and thus can be read/written using the standard file I/O mechanisms. MacOS X does the exact same thing.
I would argue that "directories as files" should be supported, but this can be done entirely at the application library level. This would mean that reading a "directory" and then writing the same bytes to another system would produce an identical directory with identical contents on that system. I would argue that this is an area where Linux should abandon Unix/Posix and really try to make something better. But it is still not an "attribute" in that there is nothing special about the internal data and it is not inserted into a database.
I also think that the Unix owner/group/date stuff is a mistake and should be imbedded in the file data somehow.
The basic problem is we need a simple block of data that 100% describes the file. To most users, the date, creator, comments, document type, etc, are all parts of the file and thus anything that does not replicate it is not user friendly. And I don't for a minute believe that application designers are only going to put "unnecessary" data into the attributes.
Therefore I think *all* attributes (including the Unix date, permissions, group, etc) are a mistake. ALL data should be copyable by reading the file and writing the same bytes to a destination. Anything else, especially a system with low-level knowledge like BeOS, is going to make computers hard to use.
If you can afford 12 9GB SCSI disks, surely you can afford a UPS! The power failures are going to seriously shorten the lifespan of your hardware (which point reboot speed is meaningless).
I have a total of 12 9GB disks, all SCSI, and I'm running them as two RAID0 devices. Both of the metadevices run ReiserFS. You won't BELIEVE how frickin' fast things are :)
Our neighborhood sees power failures almost weekly (bastards don't want me to have a good uptime, I guess :), and my box doesn't flinch. Granted, physical power up takes ages (twelve disks don't exactly spin up as fast as one :) but once the Linux kernel starts up, you can't even *tell* it's running the journal replays since it scrolls by so damned fast. It's very reliable (never lost any data), and fast.
I was doubly impressed that the kernel patching went so smoothly (linux 2.2.16 + latest (at the time) raidtools + reiserfs). One try, it all worked. Wow, open source is fun sometimes -- ever try adding support for a new filesystem type to an NT box? ;)
Read my stuff.
We don't add encryption to the files, but the other things you say are correct. Glad you had a good experience.
Journaling file systems protect you from a number of problem: system crashes and power failures. They typically protect only the metadata regions of the disk (which is the administrative information used by the filesystem to run the filesystem).
To protect against hard drive failures you want to use one of the RAID setups.
The ideal combination is RAID+Logging+Backups.
Depending on your needs, budget and speed requirements you will choose your proper combination.
Myself, I use ReiserFS in my laptop which has proved to be very helpful on my 21 gig hard drive every time the kernel decides to crash after coming back from a suspend.
Miguel.
> An OS should NEVER absolutely refuse to do what it's told to do
;)
Isn't security built around this very thing? Furthermore, devices are designed to refuse to perform an operation that would put them in an invalid state. Furthermore, as hardware moves more and more to firmware, there are bugs that can turn a machine into a boat anchor. I would very much like the OS to refuse to perform these operations.
Hey it's kind of a theological question, should the OS that can do everything be able to create a virtual rock it can't lift?
I've finally had it: until slashdot gets article moderation, I am not coming back.
> Don't try this on Linux! The ext2 fsck is horrible after a powerfail, and I've lost superblocks and had to re-install :( .
Doesn't it scan for backup superblocks? It should have created at least a dozen or so of them. At the very least, there should have been some utility runnable off a rescue disk that could copy a backup superblock.
I've finally had it: until slashdot gets article moderation, I am not coming back.
Any word on ReiserFS for FreeBSD? I've searched around, and found several people asking, and no one seems to have an answer.
I've finally had it: until slashdot gets article moderation, I am not coming back.
Heh, journalling filesystems are to handle the case of the system crashing. It doesn't sound like it's really done anything for you. :) But I suppose it's nice knowing that it's there.
I'm not sure if JFS doesn't support mixed case or is case-insensitive; they weren't clear on that point.
Case sensitivity in general is very important for Unix systems. I'm quite certain that it is required by Posix and other standards. I've seen a good number of cases where case was all that separated two files (e.g., Makefile vs. makefile) in the same directory. Now you can easily argue that this is a bad idea, but it certainly is part of our heritage, and I, for one, like it.
XFS is optimised for dealing with streaming media, and so deals well with high IO and large files.
This is not entirely true. XFS will stream media if you want using GRIO (guaranteed rate IO) features if you set your file system up that way, though I am not sure the Linux version will have that.
I would refer users to the website for a more comprehensive view of XFS. Basically XFS has been running for about 6 years on IRIX machines. It is a 64 bit file system, end to end. It is journaled. It is designed for speed, both at the OS level and at the hardware level (you can hit and sustain in excess of 97% of theoretical max drive performance in various cases with SCSI systems, and large block IO). It is designed so you can have millions of files in directories, with files in the petabyte size if needed.
Basically XFS is really one of the best file systems out there.
Saying it does streaming media is like saying Linux can be used via a vt100 emulator to edit files. It can do so much more, and it does it very well.
Combine XFS with a well designed volume manager, and you can have your file system saturate your IO bus. This is nice if you need lots of IO capability. XFS based filesystems (atop XLV) sustained 7 GB/s (thats gigabytes, not gigabits, per second) several years ago in a test, reading and writing to a single file. The limiting factor was the number of spindles one could attach to the machine. We used 864 if I remember the number correctly.
XFS scales provided the LVM scales.
This isn't true. At least as of the 2.2.16 kernel, the 2GB limit still exists. (I know for sure, since I just tried it.)
The on-disk filesystem structures of ext2 can handle files much bigger then that.
The kernel code can handle relitive seeks anywhere within the file. I'm not sure about glibc.
You run into problems with absolote seeks in programs which cannot handle a 64-bit type for the seek. This includes glibc in some cases.
dragonhawk@iname.microsoft.com
I do not like Microsoft. Remove them from my email address.
Linux isn't growing at all in the consumer desktop market.
Source?
Think hard about Linux. Who decides if you run GNOME or KDE? Not *YOU* but the programmers who write the programs you need to run.
This is sorely flawed reasoning at best, and absolutely bogus flamebait more likely.
First of all, if we except your rather flawed reasoning, then anyone who runs programs they didn't write are slaves. That includes you and your favorite OS.
But again, your reasoning is flawed. I can run KDE programs and GNOME programs and old Xt programs and even terminal programs, all at the same time. I need to have all the libraries a program requires installed, yes, but go ahead and show me a program that will run without a library it needs.
Better still, since most of this stuff is Open Source, we can take the program and re-write it to use the desktop environment of our choice. We can even change the desktop environment if we need to.
With BeOS, on the other hand, you're locked in, and cannot change it. Sounds like you're the real slave to me.
dragonhawk@iname.microsoft.com
I do not like Microsoft. Remove them from my email address.
What makes Linux bloated isn't the kernel (which weighs in just under 2 million lines, about 500,000 more lines than BeOS)...
... but all the crap around it (XFree, Mozilla, GNOME, KDE, and the dozens of libraries)
Lines of code isn't a terribly accurate measurement of code bloat. Perhaps those 1.5 million "extra" lines in Linux go to support things BeOS does not. Drivers. Platforms. Features. Stability. Security. Whatever. Maybe they're documentation. Maybe they're copyright notices. But then, we really don't know, do we? We can't know, because BeOS holds us hostage with its source code.
The nice thing about Linux is that nobody is forcing you to run all that "crap", as you so eloquently put it. If you want a stripped-down, bare-bones system with nothing but X11 and a single app, you can do that. Don't need the GUI? You can toss that, too. If you have the horsepower and the desire, you can also run GNOME with Enlightenment and every silly graphics effect you can think of turned on, plus sixteen different versions of Mozilla at once. Your choice.
That is one of the things that makes Linux so popular: Choice. We like having the ability to make decisions about we use. We like being able to choose the software that best fits our needs. We do not like companies that tell us they know better then we do, and no, we can't make changes and we can't see the source.
dragonhawk@iname.microsoft.com
I do not like Microsoft. Remove them from my email address.
I usually don't reply to AC posts, but this was just too good to pass up...
Windows95 had a minor version of this failing, in that, at the login screen, you could do a ctrl-alt-esc, select "run" and run "explorer", and get in without providing a credential to the OS.
Um, you could also just hit that "Cancel" button on the logon dialog and skip right past it...
dragonhawk@iname.microsoft.com
I do not like Microsoft. Remove them from my email address.
I don't even know what a superblock IS.
...ID3 information is injected into attributes...
So, you know very little about Linux, yet you have no problem pointing out all the things it does wrong.
Word of advice: Don't complain about things you do not understand. You don't see me complaining about implementation details of BeOS. Why? Cause I've never used the thing.
Can you please explain WHY attributes break portability?
Because they're not portable. They don't work on other systems. Anything that depends on them will not be portable to other systems. Thus, attributes aren't portable.
Is that clear enough, or do I need to draw you a picture?
You complain constantly about all of the "Linux zealots" who ignore problems in their favorite OS, yet you seem to be the biggest perpetrator of that particular vice.
Gee, like how it is already embedded in the MP3 itself? Next you'll be saying attributes can also store the title of an HTML document. What progress!
Innovation should not be held captive to those who cannot innovate.
This is true, but does it apply? Are BeOS attributes really trying to improve things, or are they trying to pull that favorite industry tactic of locking us into a single vendor? (I actually suspect the former, but I have to consider the possibility.)
The case can be made that application-level attributes do not belong in the system, but in application-level libraries. By keeping such information in the files themselves, they are easily transfered to other systems, and do not require system-level support. Meanwhile, you can still provide a standard API to get at the information with an application-library. Thus, you get the best of both worlds.
And I couldn't care less what *YOU* think is an outmoded model. The minute you can get an economist or somebody with knowledge of the industry to tell me propriatory is dead, then I'll listen. (Emphasis mine.)
No you wouldn't. Slashdot has had countless stories about such things, but you continue your tired crusade every chance you get. Meanwhile, you will happily ignore yet another legitimate complaint about your favorite OS: That anyone using it is locked into a single-vendor solution.
dragonhawk@iname.microsoft.com
I do not like Microsoft. Remove them from my email address.
I said nothing about BeOS, just the filesystem.
... BeOS VM and disk cache ...
... my BeOS machine ...
Oh really? To wit:
Obligatory BeOS plug
Not only are you a troll, you're not even a good troll.
dragonhawk@iname.microsoft.com
I do not like Microsoft. Remove them from my email address.
Yes you can. As pointed out, you can boot ReiserFS as long as your kernel containing partition is mounted with notails, and you can boot off a kernel floppy or with loadlin in any case. EXT3 will work fine - see the documentation. LILO pretty much works by reading a bunch of blocks off the drive and assembling them into a kernel, so is pretty filesystem agnostic providing the filesystem doesn't do strange things like tie together the tails of multiple files into a single block in order to save space (such as ReiserFS, hence the notails option for /boot). I don't know enough about the on-disk layout of JFS or XFS, but personally I'm not inclined to use either of them for my root filesystem yet :)
No! JFS is a good filesystem but it does not do data journalling, only metadata journalling. It is left to the application to do data journalling (like an RDBMS doing transaction logging).
You misread the post. An ext3 fs only has to be unmounted cleanly if you want to remount it as ext *2*.
I have seen the future, and it is inconvenient.
Once snapshots are ready, waiting for fsck on an FFS filesystem will become unnecessary. If a filesystem is dirty, on bootup the system will create a snapshot, and run fsck on that snapshot in the background.
ReiserFS is signifcantly faster than Ext2. I'm speaking from having run ResierFS on my computer for a few months.
A deep unwavering belief is a sure sign you're missing something...
Really? That would explain the 15 minutes my NT machine spent showing me every f*cking cluster on my 20gig drive?
A deep unwavering belief is a sure sign you're missing something...
Oh really. That would explain my posting history now wouldn't it. The last time I mentioned BeOS was a week ago, when I enumerated the advantages QNX had over BeOS. The last time I brought up a point about the advantage of BeOS was when I mentioned something about MP3s. Seriosly though. Take a look at Slashdot. People sit there everyday extolling the greatness of Linux. Maybe once a week, I bring up an occasional point about a cool UI thingy, or sometimes bring it up during and unrelated discussion (I brought it up when I was defending client-server graphics systems a while ago). If you actually look at my post history, I only ocassionaly say something good about the OS. People look at the name, "be-fan" and think "oh, every post he puts up must somehow be connectected to BeOS." Even you fall into the trap with this post. I said nothing about BeOS, just the filesystem. Believe it or not, AtheOS uses a very similar file system to Be's, so its not exactly a BeOS-only message.
/.ers who go on about how great Linux is. There doesn't need to be one more.
As for consantly bitching about Linux, I try to be the devils advocate. Don't get me wrong, I have nothing against Linux. I have used it a lot. The problem is that people are so blinded by their frevor (or their elitism) that they really can't see when Linux has a fault. The mindcraft thing is the perfect example. While Slashdotters spent the whole timing bitching about how mindcraft was evil, Linus and other sane people actually took it seriously, and improved the kernel as a result. Or take the whole NVIDIA debacle. Not once did people mention (in their frevor to say Linux was almost as fast as Windows) that the Linux drivers were had tweeks similar to the Windows Detonator 3 drivers. So the test was essentially Detonator3-Linux vs. Detonator2 Windows. After the Mindcraft thing you would have thought Slashdot would rip it to pieces. But they didn't. Instead, people started preaching about how Linux was going to own the desktop market in a year (I'm not exaggerating) That's the kind of stuff I have problem with. I have no desire to be one of those people who constantly extolls the virtues of something. I will bring up BeOS once in a while, but usually just to illustrate a weakness of Linux (or OSs in general.) I have similarly brought up NT to point out weaknesses in Linux as well, so that's nothing unusual. There are enough
A deep unwavering belief is a sure sign you're missing something...
When did I say something about BeOS? I'm talking about bfs the file-system.
A deep unwavering belief is a sure sign you're missing something...
Why is it such a problem? Unlike the Mac, BeOS attributes are not flaky. (For example, files aren't chained to the program that created them.) BeOS stores file-types as a MIME attribute. So if you want all your /text-html files to be opened by a particular problem, its just as easy as going to file-types and associated /text-html with StyledEdit. Its the exact same thing as going to the GNOME control panel and associating ".html" with GEdit, except you don't have any ugliness in the file-names, and the system automatically figures out what type files are. If you don't like attributes in general, then please explain why.
A deep unwavering belief is a sure sign you're missing something...
Tell that to all the BeOS people. Seriosly though. If I talk about the advantags of bfs during a discussion on file systems, does it automatically mean that I'm saying "Linux sux, BeOS rules?" I never said ANYTHING about BeOS. I'm talking about the filesystem!
That said, your arguement has some merit. A bunch of important software WAS canceled. However, you're not totally right that BeOS is dying. Software is coming to the OS at quite a good clip. We've already got a good video editor, and other media programs are being made. BeUnited is helping a lot by starting projects to address gaps in the software line. Tracker and deskbar has been OSSed (under something similar to the BSD license) so the GUI wil continue to evolve. The system is modular, so the system itself can be improved by users. BeOS is far from dead.
Your point about the focus shit is totally off base. Be never said that BeOS is dead. They focus shift-ed. Sure, it sounds like a cop-out, but consider this. BeIA and BeOS are more or less the same thing. Be's plan is to be able to pull out a BeIA release out of the BeOS source-tree anytime it wants. Meaning, that any cool stuff integrated into BeIA gets into BeOS too. And this is not bullshitting on the part of Be. OpenGL, Java, networking, and a good browser are all critical for BeIA. And they're important for BeOS too. So guess what, Be is bringing them to BeOS! And before you say, "oh, that's just vaporware" remember, a lot of these things are in late beta. www.betips.net is already running on the new BeOS networking architecture, a lot of people aready have the OpenGL beta, Java-personal has already been ported to BeIA, and Opera is already working on a web-browser for it. (The Opera browser hasn't been released yet, but already works and can pass standards complience tests.) And with Compaq making a BeIA-powered IA, you can bet that these technologies are going to get to the public.
A deep unwavering belief is a sure sign you're missing something...
1) probably true, that Linux wouldn't need reinstalling in these case. However, I'm not going to take time to fix what fsck can't. It is easier for me to just copy over my CD-backup than to fix the fs. Seriously though, if fsck gives me a "lost superblocks error" and the system won't boot into multi-user mode, then what the hell am I supposed to do? I don't even know what a superblock IS.
4) Can you please explain WHY attributes break portability? How exactly does it lock you into the OS? You forget four things:
1) Dealing with attributes is required for anyone writing a BeOS fs driver. Thus, any attribute data can be extracted by the fs driver if they are reading a bfs disk from another system.
2) The system takes care of attributes when sending things outside the OS. If send a picture to a non-BeOS user, the attributes are stripped out. If you copy stuff to a non-bfs disk, then attributes are taken out. If you post something, the appropriate extensions can be added. Its not a big stupid system that automatically makes file prorpiatory. If you're using a GIF file laden with attributes, it will still be a gif file when you send it to a Linux user. They just won't get the benifets of the attributes.
3) Attributes kick ass! No stupid MP3 database programs, ID3 information is injected into attributes (which are stripped out when you send them to Napster!) and the FS serves as your database engine. Email can be indexed by user, sender, date, time, subject, whatever. You can set up custom searches to get all email from your boss written within the last 5 days. Best of all, there is no central database to take care of, since all this info is in attributes. Think of it as UNIX-style file data (creator, data, group-info, etc) taken to the next level.
4) Innovation should not be held captive to those who cannot innovate. Nobody if forcing you to take advantage of attributes. If your cross platform program needs to share the same file-types between OSs then DON'T STORE ANYTHING IN THE ATTRIBUTE DATA! Keep a central database or whatever you want. However, if you couldn't give a flying fuck if other OS can take full advantage of your files (as long as they are a standard type, other OSs will always be able to *READ* them) then by all means, take advantage of the technology.
And I couldn't care less what *YOU* think is an outmoded model. The minute you can get an economist or somebody with knowledge of the industry to tell me propriatory is dead, then I'll listen.
BTW> BFS is documented in a book, and an GPL'ed clone is part of AtheOS. Go have fun with it.
A deep unwavering belief is a sure sign you're missing something...
Really, or are you being anal?
A deep unwavering belief is a sure sign you're missing something...
No you can't. Lilo won't boot a ResierFS partition. You have to make your /boot partition an ext2, and another ReiserFS partition for /usr and everything else. I would guess the others are similar.
A deep unwavering belief is a sure sign you're missing something...
ReiserFS is signifcantly faster than Ext2. I'm speaking from having run ResierFS on my computer for a few months.
A deep unwavering belief is a sure sign you're missing something...
I can run my Japanese car on my American roads without importing Japanese roads. And if I move my Japanese car to German roads, I automatically get the benifits that German roads provide. You just don't do that with GNOME and KDE (or most other software) Sure your running KDE, but the app is still running GNOME, and has all the issues that made you run KDE in the first place. The software industry is *FAR* behind the rest of the world in making products interworkable.
A deep unwavering belief is a sure sign you're missing something...
I think that would only happen when you were genuinely exceeding the transfer speed of the disk, in which case, "you dummy". tux2fs probably *will* take more memory (substantially more?) than ext2 or a journaling filesystem, but with the amount of memory that most systems have available for file cache, I doubt that is a problem.
Embedded devices that need consistant IO rates with little RAM for buffering probably want to look at a journaling FS.
> What they don't realise is that neither NT actually has a Journal File System
x fs_white_paper.html
Bullocks. NTFS is a Journaling File System, albeit a crippled one, due to the fact that NTFS only journals META-DATA, not DATA.
http://oss.sgi.com/projects/xfs/papers/xfs_white/
http://www.executive.com/whats-new/whitepaper.asp
--
"We don't need no stinkin Karma" - 3 Amigos
> migrating my come server to it
;)
You must have some really valuable pr0n to need a journaling FS for it
Mike.
Tales from behind the Lagom Curtain
i already posted this once when discussing xfs beta article. anyway there is great article on journaling filesystems at linux gazette.
it explains different features and concepts related to the 4 different journaling filesystems. XFS, JFS, Ext3 and ReiserFS.
-- http://electronicintifada.net --
Back in the old days (around 1994) one had the choice between minix, xiafs, ext and ext2 as filesystems for ones linux box. ext2 stayed
Today we face another choice and I sure that is darwinian way we'll select the right next generation filesystem.
The big difference is however that the filesystems that existed back then didn't have any money (companies) behind them who could blur the choice and ext2 survived because of its technical superiority over the others.
Something else that may lead to different filesystems suviving is that the Journaling filesystems mentioned all have their own disign and possible uses. On some systems it may be worth the performance penalty for data security on others it may not.
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open Open for writing starts a new version of the file, which initially shares all the pages of the old one. Writes are copy-on-write, so you can append to a file at low cost. Until the file is closed or committed, other reading processes see the old file.
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commit Commits the file; the new version replaces the old one. This can be done without closing the file.
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revert Reverts the file to the last commit; the old copy becomes the current one.
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close Commits and closes the file.
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exit Commits and closes all files.
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abort Reverts and closes all files.
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SIGKILL, etc. Works like abort.
This gives database-like transactions at the file level; either the update happens completely or not at all. There's an "unfrozen" file mode, for files that aren't updated as a unit and need to be looked at by other processes during update, but it's not needed much.Transactions are really valuable when accessing a remote file system, where you may lose connectivity during an update. LOCUS was a distributed UNIX in an era when networks weren't very reliable, so that made sense.
XFS and JFS allow an easy migration path to/from "mid-sized" iron to/from Linux. If you have a JFS volume from an RS/6000 you want to mount on Linux, you're out of luck with XFS, you need JFS. Same thing with XFS and SGI. This is a major migration issue in shops that have these boxes.
Also, there is the issue of IBM openly supporting, lets say XFS. While that might make good business sense, it would mean lots of bad PR and midshare loss.
The "market" will eventually make the winner(s) the defacto standard, but it never hurts to have direct support for other fs's you may need to interact with. I use support for the windows file systems all the time (fat32), but I would never dream of really using it as a main Linux volume....but it is always mounted.
-Pete
Soccer Goal Plans
It appears that this is NOT something to hold in opposition to Ext3 - but rather that this is part of the latest versions ext3!
Sort of like saying: "Forget all that Red Hat and Debian crap... LONG LIVE LINUX! " ?
Thanks for the link, however.
I have no problem with your religion until you decide it's reason to deprive others of the truth.
No, not exactly. It'll log changes to the filesystem, so it knows possible failures after a crash, but it 's not capable of rolling back, for recovering data. I don't think that is even a bad thing. The filesystem would be slower then, and applic. that need robustness (databases) have built journaling anyway.
(-% TwistedMind %-)
Comment removed based on user account deletion
I installed the ReiserFS kernel patch and utilities today, and just finished replacing all my partitions with ReiserFS partitions. Let me tell you why I chose ReiserFS over the other three mentioned.
Biggest concern is stability. Ext3 is version 0.0.2e, which is not a reassuring sign. JFS is 0.0.3 (or somewhere around there), again not very reassuring. I don't know the version number of the XFS port, but it does say on the website something about the FS port being beta, and that it "may damage" data. Furthermore, it is only available for kernel 2.4.0, which doesn't seem to work with my sound card module (I'll never by a product based on Aureal hardware again). ReiserFS is up to version 3.5 on stable kernels, which indicates that it's been around for a while. Plus, the testimonial on their web page says sourceforge uses RFS for half their servers. If it works for them, I figure it works for me.
Another problem with Ext3 is the fact that it's just Ext2 with journaling grafted on. I want a filesystem built around journaling, not journaling built around a filesystem.
XFS and JFS bother me because they are early ports of software for different platforms. I trust Ext3 over either of these, simply because Ext3 was meant specifically for Linux. If SGI or IBM can make their ports stable, they'll be worth looking into.
RFS was built from the ground up as a Linux-native, journaling file system. People have used it and loved it. I love it too, at least as much as I can after knowing it for only a few hours. I've reset it a few times now, beaming as the screen says, "3 transactions replayed in 2 seconds" and mounts my partition, rather than saying "fsck forced... 1%...2%...3%..." and mounting my partition five minutes later. So far, I've not found any lost data. The only thing that bothers me is the lack of extended attributes, but I never use them anyway.
FSCK forcefully wiping out data in order to boot was what sent me crying back to WinNT about a year ago. It was the only grudge I held when I went crying back to Linux from NT two months after that. I treated my power button delicately, and shut my PC down every time a thunderstorm started.
With ReiserFS, this could be the beginning of a beautiful friendship, where I can tempt the fates by continuing to work in a thunderstorm, and I don't have to tremble with fear that I might accidentally pull the wrong cord if I need to unplug something on the same outlet as my PC.
Whether it's XFS, JFS, RFS, or Ext3, at least we can say that NT no longer has ANYTHING over Linux. Choice is good.
I do not belong in the spam.redirect.de domain.
"I think that XFS and JFS should both be integrated with it. ext3fs is only useful for scared admins, as it has none of the basic speed advantages of the others"
f
XFS is a journaling system on it's own and it is SGI's crown jewel achievement - It does not need to be integrated in any way with ext3 as that is not the goal here. Eventually XFS on linux will be used with CFXS which is journaling with clustering which ext3 does not support. XFS on IRIX is one of the fastest journaling file systems on the market and it scales incredibly high. No other Journaling system for linux, not even reiserfs, can match the speed or scalability of sgi's xfs.
On a side note, I use reiser on my box at home and I'm very pleased with it. It is not however, as fast or as scalable on an enterprise scale as XFS. For more info on XFS please see http://oss.sgi.com/projects/xfs/papers/xfs_GPL.pd
The specs are impressive. While the code is beta, they hope to achieve the same level of performance on linux as has already been achieved on IRIX.
Do you really mean that JFS doesn't support mixed case filenames, ot did you intend to say that JFS is case insensitive? I know I'm not the only one who thinks that case sensitivity is something that should be reserved for the written word and passwords. Mixed case filenames are fine, just don't force me to use them -- C makes it really easy to shift a byte's value by 64...
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"A witty saying proves nothing" - Voltaire
Okay, so which one is closest to replacing Ext2? I am having a hard time finding information on what to expect from the new kernel FS. Will 2.4 ship with one of these? Do any or all of them break the 2GB filesize limit? With 2.4 so "close" to release, you'd thing there'd be more *easily* available info out there (I'm sure it's there and I just can't find it...
http://www.globalfilesystem.org
A file system for SCSI over fibre that have journaling.
I'm curious...does anyone know how much more RAM/CPU Tux2/ReiserFS/... need over and beyond Ext2?
I wrote about RAM in another article - Tux2 won't use a lot more, and because of its ability to throttle the dirty cache, could use significantly less than we're used to.
As for CPU - I haven't really noticed a big difference vs Ext2 but I'm not in real-world testing situations yet. The only CPU intensive thing Tux2 does is make extra trips into the block allocation bitmaps. There are roughly zero extra trips the first time you write a file, and 100% extra trips if you rewrite the file without truncating it first - actually, a pretty rare thing to do. A database might do it though, and for that case I'll provide a per-file disable of the copy-on-write - the metadata will still be protected but the database will be responsible for doing its own crash recovery for the file data, which most databases do pretty well. In fact, the phase tree algorithm started life in a database.
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Have you got your LWN subscription yet?
Everyone loves to ask those really stupid questions about combining open source projects. Being an open soruce developer, I find these very irratating. The following reasons should be enough to either make you understand, or prove you can't understand...
- Compatition is key to all things being good...
- Each FS has an almost compleatly different techincal design, and each has a chance of being the "best" general purpose FS.
- Each FS might in fact be the "best" at some things
- Each developer is working on their respective project because they think it is the right thing to do. You tell them "No, stop that work on your project and help this one" and they will. They will see that the comunity thinks of their project as meaningless wheel-reinvention and quit.
There are many more reasons that others will point out as well. Look at other industries. Why are there different radio stations? Different cars (even made by the same company)?
Hey, if I stop one more person from telling my friends and my self that we should join this other project or that then this note is worth it.
Got a problem with my view? I'm easy to find.
Jamie B
As far as I can tell, all of these filesystems allow files vastly bigger than 2GB, but the interface between VFS and LIBC still nicely enforces the 2GB limit for most purposes.
This is the wrong thread on which to try to find resolution to that issue; take it up with the folks that defined ISO and ANSI C...
If you're not part of the solution, you're part of the precipitate.
Avoiding the obvious question of why can't the effort going into four diffrent projects be channeled into one
That's like asking all the *BSDs to work together with Linux. Diversity is a very good thing. Personally I think SGI's XFS is going to kick some serious butt since the SGI folks are all for high performance and huge I/O throughput performance. They've also shown they can do it (on Irix). Not that the other parties will stay behind. I just think SGI has a better chance at dominating the Journalling FS landscape in Linux...
-adnans
"In short: just say NO TO DRUGS, and maybe you won't end up like the Hurd people." --Linus Torvalds
I have production systems now using Ext3, which is little more than Ext2 with full data journaling (and completely reversable). This is NOT an endorsement of Ext3, but the fact is that it is the only use usable at this point (largely because it is just a slight evolution from Ext2, unlike the others).
I am in the middle of a ~30 page HOWTO on NFS+Journaling. Contact me direclty if you are interested in a copy. Again, I have production servers and workstations running with Ext3 and sharing data out via NFS v2/3.
-- Bryan "TheBS" Smith
-- Bryan "TheBS" Smith
Independent Author, Consultant and Trainer
Okay, today, I'm actually going to preach the benifets of a BeOS technology.
.stupid-extension because file-type is stored within attributes. The user and edit attributes all they want, and custom file info (like gamma-info for a GIF) can be imbeeded into a file. For example, if you've got a special program that can display a GIF with variable gamma settings, it can embed those gamma settings into an attribute. Those attributes are ignored by other programs, and stripped out when sent to another OS (unless you use .zip compression.) However, when displayed in a program that recognizes that attribute, it can be used.
With all this talk of journeling file system, I'm surprised that bfs got ignored. BFS has several things going for it:
1) It's fast. While it is a journaling file system, on Bonnie, it is about 20% faster than my ReiserFS partition (which is closer to the outside of the disk too) on straight reads and writes. It is also a good bit faster on the per-char tests. Best of all, the CPU utilization is 30% lower than Linux in the sequential, and 50% lower in the per char (where Linux pegs the CPU). However, the rewrite tests, it is significantly slower. Something I think has more to do with the BeOS VM and disk cache than the file system.
2) It is ever so solid. I regularly (read: three times a week) shut down my BeOS machine with my power button. Not yet have I gotten a lost file, block, or data corruption. Linux regularly needs reinstalling if I turn it off in the middle of something important, and even NT bugs out on me for not shutting down. (I just hosed the system two days ago.)
3) It has had database capabilities for years, while ReiserFS still has them in planning. That might be a "gee-whiz" features, but nothing beats having your MP3s automatically entered in a database based on ID3 info. (Or emails, or pictures, or whatever.)
4) It has a flexible system of attributes. No more
A deep unwavering belief is a sure sign you're missing something...
Uhm, no.
:)
Linux 2.4 has a set of 64bit file calls which work natively on 64-bit achitectures, and work also on 32-bit architectures by using double word operations. You take a performance hit on 32-bit systems, but it works fine. The glibc 2.x has it, as does the kernel. You just have to ensure that the libc was compiled with support for it.
Remember, this is opensource. We've patched the libc and vfs layer with little trouble because of it. Now it just needs testing
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Internet Explorer (n): Another bug -- that is, a feature that can't be turned off -- in Windows.
You have to remember that XFS and JFS journal all data and metadata changes whereas ReiserFS and EXT3 only journal metadata. Thus, [XJ]FS protect your data from becoming corrupted where the others just help you boot faster after a crash (with respect to their journalling).
Ext3 can be used (once it's stable) on a preexisting Ext2 filesystem. The others cannot directly migrate from anything 'official'.
I like the ideas of all four. It may be that you want to have a combination of all of them in your system, but that would be pushing it.
I've used JFS a lot and it is really bulletproof if you set it up properly. It's heavily tied to the LVM in AIX, so I wouldn't expect much progress without LVM for Linux being a stable API. So, call it post 2.4.0 at least.
At work I have five workstations and two servers running ReiserFS. These have performed flawlessly over the past several months, as they have been eased into production.
The ReiserFS folks have been really good about finding and fixing bugs. Recently, a bug was discovered which crashed the system with ReiserFS-3.6 systems if you saved a file from Star Office on top of itself on an NFS server. That bug was eliminated with ReiserFS-3.6.17 in just a few days after being reported.
Since ReiserFS isn't merged into the official kernel tree, when you want to try out the latest kernel, you have to patch ReiserFS into the system yourself, but that is quite easy.
I look forward to the day when ReiserFS and these others are merged into the kernel. By the way, the 2.4 kernel is quite nice. Try copying a file several times your memory size from one disk to another (a 600 mb iso image should do the trick) on both 2.2.x and 2.4.0-test9pre-whatever. And try to do something with your system during the copy. You'll become addicted to 2.4.0, I promise you. Its wonderful.
I'm curious...does anyone know how much more RAM/CPU Tux2/ReiserFS/... need over and beyond Ext2? Journaling is an impressive feature, yet some of the machines I monitor aren't cutting edge; Pentium 200/64MB, Celeron 300/96MB. I've already tweaked these systems in other ways (no extra consoles, MTTR settings, ...).
A firewall can not protect you from yourself. Turn off what you do not need. Do not use the firewall to do your work.
Haven't we had this discussion umpteen times before? Such as... two days ago? There's even a link to a discussion on the four competing filesystems. Sheesh. Flogging the dead horse.
I was ASKED to install a Linux system at work last week! (I've been /home on it, and since I was logged in as root, it didn't matter.
preaching Linux for 3 years - patients pays off!) They gave me an
old P100 with 71MB or usable RAM and two HDs.
I decided to use SuSE 6.4 BECAUSE it had ReiserFS.
The graphic install really impressed the Win techies standing
around watching because it was easy enough that even they
could do it, and is pretty eye candy. KDe really impressed them
too.
Thirty minutes later the second HD, a 4.3 BigFoot, died.
I had
The dead drive was smoothly disconnected from the system.
Since I was needed to power down to replace the HD I decided
to test out the ReiserFS. I reached over and pressed the reset
button. A collective "gasp!" rose from the assembled techies.
Thirty seconds later I had the KDE graphical login prompt.
No corruption, no losses. It's like having an UPS attached.
I didn't notice any increase in speed of file accessing, but it
was fast at rebooting. It's been up 18 days now, which is
also impressing the techies in our M$ shop. They are still
afraid of Linux though. I think it is because they may feel
that they may have to retrain, loosing any employment
advantages they may have accumulated. They are right.
Running with Linux for over 20 years!
McKusick's Soft Updates has also a nice feature: unlike the journaling file systems, it does not have the burden of writing blocks to a logging device. So a soft-updates enabled kernel runs at the speed of traditional asyncronous file systems (ie, default ext2) while providing a very good level of reliability (it is not a syncronous file system, so it runs at a very enjoyable speed).
You can boot a Soft Updates file system without fscking it, the file system will be in a functional state. The only problem is that you might start to loose free blocks that are believed to be busy. So every 100 or 200 crashes you might want to run fsck to free those 100 blocks.
I agree with you regarding the ext2 file system when running in async mode: when there is a lot of activity on the disk, and a lot of changes to the file system, crashing an ext2 file system will loose a considerable ammount of data. ext2 fsck will not be able to recover your file system properly (it has happened to me a couple of times already).
For non-SoftUpdates kernels and non-Journaling kernels, if you are running a system with sensitive information, I suggest turning syncronous access on the file system (add option sync to it).
The sad part here is that the BSDs have traditionally been optimized for the syncronous case, so they run at acceptable speeds. Linux ext2fs has never been optimized for this case so in practice it is very slow.
I am using ReiserFS on my laptop, but on a server, if I had to choose, I would run SoftUpdates for BSD kernels and ReiserFS for Linux kernels.
Miguel.
When I was at the Ottawa Linux Symposium, there were talks on XFS, JFS, and ext3fs. It seemed clear that XFS was near beta, so the recent announcement was no surprise. Ext3fs also sounded near beta. Ext3 takes the simple approach of adding journaling to ext2 in such a way that as long as you unmount cleanly (so there's no need to play the log back), you can take an ext3 partition and mount it as an ext2 partition. From the talk, it sounded pretty much ready.
JFS was another story. My take on the talk was that people who atteneded it learned one important thing: JFS is the journaling file system to ignore. The Linux port comes from OS/2, instead of directly from AIX. It lacks such things as support for mixed case filenames. The answers to most of the questions were, "We hadn't thought of that," or, "We'll have to look into that." If JFS didn't have the "me-too" ego of IBM behind it, the developers would have realized that they were better off working on one of the other file systems.
I tried to ask this question a few months ago, but with no luck getting it posted I did some research on my own. I wanted to make a 60GB file server that would give me some insurance on my data. I was close to using the IBM JFS, but kept hearing about ReiserFS and gave it a try. (Heck, sourceforge uses ReiserFS on their servers, so it's good enough for mine.) Anyway, after a little more reading, I realized that ReiserFS doesn't just add journaling to a partition, it also restructures the filesystem into B-trees which can enhance access speeds, and it also adds a bit of encryption to the filesystem since it uses a hashing algorithm to sort the files.
In my opinion, you just get more. I also found the installation and recompile fairly easy to do. I've been using ReiserFS for the past 3 months with absolutely no problems.
Sometimes I doubt your commitment to Sparkle Motion.
tux2fs probably *will* take more memory (substantially more?) than ext2 or a journaling filesystem, but with the amount of memory that most systems have available for file cache, I doubt that is a problem.
.1% of the total in a filesystem. My guess is you won't notice any extra load on the buffer cache.
I've analyzed that question and I think tux2 will only use a little more cache memory, not a lot more, and it could even be less - see below. Tux2 uses per-block copy-on-write, and when the old version of a block won't be used any more (the normal case) that means you can just change the disk block number in the buffer - no extra memory used at all. The only time extra memory is used is when a file block is written over and over again, every 10th of a second or so - then you will sometimes get two copies of it in memory at the same time. The first copy will disappear as soon as it finishes being transfered to disk. This kind of writing pattern is rare with normal data but is common with metadata. Fortunately metadata is about
In fact, I think Tux2 will take a load off the buffer/page cache because it doesn't let dirty data hang around a long time - it starts writing to disk a fraction of a second after you start writing to a file. My plan is to have Tux2 shorten its phase length under heavy memory pressure, so the space needed for dirty buffers will drop down to just 100-200K, and you'll still get good performance.
Cache memory for reading under Tux2 is the same as Ext2 and most other filesystems.
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Have you got your LWN subscription yet?
XFS is optimised for dealing with streaming media, and so deals well with high IO and large files.
JFS has been around for years under AIX. It's a well proven general purpose journalling filesystem.
ReiserFS is the best established of the Linux journalling filesystems. It has several fairly innovative features and is more efficient than ext2 in terms of space utilisation. People are using it as their primary filesystem now, although it's still in development.
EXT3 is (unsurprisingly) a development of EXT2. It lacks most of the pretty features of the other journalled filesystems, but has the significant advantage that you can turn EXT2 partitions into EXT3 (and vice versa) without any trouble at all.
For similar crash protection, you might want to try out McKusick's "Soft Updates" that appear in *BSD systems. Essentially, they are ordered disk writes that makes sure data gets on the disk before metadata is altered. They go through the buffereing system, so performance isn't bad.
:( .
As an experiment, I pulled the plug towards the end of 5 FreeBSD kernel compiles (SMP `make -j 4`). In all cases, the fsck upon restart was minor, just freeing inodes. In four of the cases, `make` just picked up where it left off, and finished the kernel compile, losing only ~40 seconds work. In one case, a `make clean` had to be done because something was incomplete.
Don't try this on Linux! The ext2 fsck is horrible after a powerfail, and I've lost superblocks and had to re-install
It is also proof that open source software does not just 'chase tail lights' - the work is substantially innovative.
Phillips is also implementing tailmerging (a feature from ReiserFS to efficiently store small files) for ext2/ext3/tux2.
For more details, check his web pages here, and the linux-fsdevel mailinglist.