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ext3fs in Linus' Kernel Tree 384

Posted by michael from the journaling-for-the-unshaven-masses dept.
peloy writes: "According to Linus' changelog for Linux 2.4.15pre2, the long waited ext3fs, the sucessor of ext2 with jounaling capabilities, has finally made its way into the official kernel tree. I have never tried ext3fs but it looks that now that it is "blessed" by Linus I'll be upgrading my old and trusty ext2fs partitions soon."
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ext3fs in Linus' Kernel Tree

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  • ...and there was much rejoicing.
    • ...nor did I hear an explanation of how this wound up in a 2.4.* kernel instead of 2.5.*, where right now it really belongs, even though AFAICT it's dead stable.
      • how this wound up in a 2.4.* kernel instead of 2.5.*, where right now it really belongs,

        Heck if we can swap out the VM midstream, this is nothing :) Actually I think Linus was VERY smart to push the new VM into the kernel. Why? Because I believe he avoided a LOT of people running patched kernels until 2.5 was released. It was obvious the 2.4 VM was broken. Had he held off, folks would have realized (though probably slowly) that the new VM was better and they'd have patched it in anyway.

        The same holds true for ext3. RedHat is already shipping it with RH 7.2. Its rock solid from their standpoint. So it makes sense to include it in the stable kernel. Sure, we all wish Linus had the ESP ability to have known to include these things at 2.4.0 (wait the new VM didn't exist then :) ) but given current circumstances, these are smart moves. Otherwise we'd all be patching kernels for another year to get ext3 (if we wanted it) and the new VM.

        Yes, I realize patching kernels is a fact of life - I do it all the time to get XFS for my desktops and servers, but the less patches I need to worry about the better.

        We can stick our noses in teh air and talk about how Linus never let big feature patches into the kernel before - well, everyone is allowed to change their mind. Besides, its not THAT huge a deal. If you're worried about stability, stick with what works. But if you need newer features for your setup, you can use a more recent stable kernel.

        In the end, this ensures stuff in high demand sees production use earlier. If we waited to 2.6, you'd just be delaying it to far, not just for the new kernel development time, but also the 'I can't use 2.6.0 in a production box) so you'd wait until a later release. Just like you've waited to deploy 2.4.x production, right? :)

        Things change. RIght now, I'd say for the bulk of the production systems, the smart move is to wait until Linus hands the kernel off for maintenance. Once that happens it'll see MUCH less churn. Befure we had 2 release stages... 2.x where x is odd for development, 2.even#.low# for release beta, and 2.even#.big# for stable production ready kernels I think thats a good thing. Besides its all relative - saying Linus shouldn't put x, y, z in the kernel because the last number is too high is pointless. We just need to adjust to the new release schedule!

        I'm glad 2.4 has what it has. Now hopefully 2.6 will have XFS and I can run vanilla kernels again (nah - never gonna happen :) )

        • Ugh - really wish that edit feature was in slashcode :) I never seem to catch them all in Preview!

          What I meant to say in the paragraph near the end was we used to have a two stage release cycle: 2.odd for development and 2.even for stable prodcution, now we have a 3 stage release. 2.odd for development, 2.even.low# for large scale beta test and late features, and 2.even.high#/maintenance handoff from Linus for production stable releases. I think the latter is a good thing.

      • I believe Linus has learned to be a little more realistic with releases. While publicly he states that he doesn't care a hoot about what any polls, groups, or the press want or think, and is only interested in building the best dang kernel, my guess is that he desires to see Linux really catch on in the corporate world (and I'm talking linux vs other unix - not displacing MS.)
        The corporate world really wants to see business features in the production kernel such as a rock solid good performing VM, a journaling file system, etc. The older kernels' VM and lack of journalling were really singled out as being critical hurdles for corporate acceptance.

        It didn't matter that RedHat had ext3 or ReiserFS, it was needed in the base kernel without messing around with patches. It's more of a mindset / perception thing than reality.

        The fact is, the corporate world wasn't going to wait another 2 years for 2.6. Those features really needed to be mainstream now. The only thing I'd really like to see added are extended ACLs, but that can wait. I don't know if a solution to device numbering can if Linus won't assign new numbers... (Alan will however, in his tree...)

        Thanks Linus! And a big thanks to all the hundreds of other kernel hackers that made this all possible!
      • I think it's fine to put it into 2.4

        1) People are already using it and it seems stable

        2) Alan already had it in his tree.

        3) Putting it in makes life easier for Marcelo Tosatti. If Linus and Alan both agree that it should be in the kernel then people think it probably should be. If Marcelo includes ext3 on his own, people would question his judgement. On the other hand if Marcelo leaves it out and Alan stops producing his -ac tree then people who have been using ext3 will be upset.

        4) Ext3 doesn't change anything.

        5) You still can use ext2 if you want.

  • Hurray! (Score:2, Interesting)

    by __david__ ( 45671 )
    I've been running with the ext3 patch for a couple months now and I really like it. There's nothing like locking up your system while testing some crazy hardware, and booting back up with no fsck... I'm glad its finally "blessed"!

    Yay!

    -David

    • The only time I've ever seen it upset was when someone ran zgv at the same time as XFree86v4.1 (on a CyberBlade-based mobo video) and caused a hardware insanity then lockup while they were writing config back to /etc... ugh...

  • Finally! (Score:3, Informative)

    by alien88 ( 218348 ) on Saturday November 10, 2001 @03:07AM (#2547740)
    I've been running ext3 for about a month now, and it is so much better than ext2. I'm glad to see that Linus decided to merge it in. I know that there were some issues for a while with ext3 not working with the new VM, but they finally started releasing patches for the latest 2.4 kernels.

    -Alien88

  • ext3, a journaled ext2 and not much more... (Score:5, Informative)

    by SpamapS ( 70953 ) on Saturday November 10, 2001 @03:08AM (#2547743) Homepage
    I've been using ext3 ever since I upgraded to 2.4.14 a few days ago. Its nice to have the journaled FS... as I have been testing out a lot of !cough!nvidia!cough! proprietary drivers and bleeding edge software lately, and subsequently crashing. W/ ext3, I can get back to the crashing very quickly.

    That said, I also use ReiserFS for some other things(try /var first, its simple to convert). It definitely speeds up the directory access... and on my squid it cut the average response time by a full half second... :-P.

    I personally think ext3 will win out, as it takes about 20 seconds to convert a 6GB partition... vs. XFS or ReiserFS taking nearly 10 minutes, and much more complexity.

    • Well.. (Score:5, Insightful)

      by mindstrm ( 20013 ) on Saturday November 10, 2001 @11:18AM (#2548393)
      I don't judge a filesystem based on what kind of tools are there to 'convert' it from something else. That's not what it's designed for, and has nothing to do with what you get out of it.

      No kidding ext2 takes seconds to convert to ext3... it's the same filesystem.
      • Well, ext3 is very easy to test out, and it will soon get a large Userbase. More users means it's getting more attention, which in turn means more development. The different journaling filesystems are not too different from each other considering performance (and that's what most people are concerned with), a while ago reiser was the best performer AFAIR, but with more development going into ext3 that might soon change. I think it makes sense to put your bets on the Filesystem where you expect the most development to happen.
        • Yes. I like the fact that ext3 is an addition to ext2 as well...

          I don't expect that much development into ext3. Why? It has a clearly defined goal: Journalling. Once journalling works, and is optimized... that's it.

          Reiserfs, and others, have many other features as well.

  • Some important points... (Score:5, Informative)

    by ThatComputerGuy ( 123712 ) <amrit AT transamrit DOT net> on Saturday November 10, 2001 @03:18AM (#2547757) Homepage
    Of course we'll have a lot of posts here talking about the issues of backwards compatiblity, ext3's offerings, etc, so we migh as well get those out of the way now.

    From what I understand, ext3fs is just ext2 with journaling support, so in the (somewhat rare) event of a system crash you don't have to go through a time-consuming fsck during the next boot. Results in better data protection and more uptime.

    If an ext3fs enabled kernel on an ext3 partition needs to go back to a previous kernel for some reason, or say, you forget to compile ext3 into a kernel, any ext2 kernel will still be able to read/write to an ext3 partition, as long as it was cleanly unmounted with the ext3 kernel.

    Why not push ReiserFS, XFS, etc? It seems that most of these are not very well proven yet. ext2 is tried and true, kernel support is good, and the new revision adds journaling, so why not stick with ext3?

    AFAIK, these are some of the most FAQs about ext3. I wonder how often they'll show up below...
    • : Why not push ReiserFS, XFS, etc? It seems that : most of these are not very well proven yet. ext2 : is tried and true, kernel support is good, and the : new revision adds journaling, so why not stick : with ext3? Bzz. Try again. XFS is extremely well proven. It's been in use for years in systems with massive storage - nuclear war simulations, automobile designing, and the area I've been dealing with the last several years, weather forecasting.
      • I believe by that comment he meant "the Linux kernel support for ext2 is well-tested and stable, while that for XFS and Reiser FS is not." It's their Linux support that's problematic, not the filesystems themselves.

        And I'm tempted to disregard any arguments that start with something as ridiculously juvenile as "Bzz. Try again."
    • From what I understand, ext3fs is just ext2 with journaling support,

      Yes and no. Functionally, that's strictly true. Internally, ext2 and ext3 have diverged somewhat. Ext3 does not share any common files with ext3 at this point. Ext3 is still buffer-oriented, wheras Ext2 has largely been converted to use the page cache. The page cache aspects of ext2 are expected to be added to ext3 in due course. At some point, there may be a full merge of the two code bases, though that's going to be a fair amount of work.

      • Re:Some important points... (Score:2, Funny)

        by Anonymous Coward
        >> Ext3 does not share any common files with ext3 at this point.

        So now there's a code fork, and the only difference is case sensitivity?

        Yeesh, and I thought having to distinguish between stdlib "FILE" and kernel "file" was bad.

    • Re:Some important points... (Score:4, Informative)

      by dbarclay10 ( 70443 ) on Saturday November 10, 2001 @05:37AM (#2547973)
      I'd just like to clarify some of this post's points:

      From what I understand, ext3fs is just ext2 with journaling support, so in the (somewhat rare) event of a system crash you don't have to go through a time-consuming fsck during the next boot. Results in better data protection and more uptime.

      That's not entirely true for a couple of reasons; first of all, the ext3 code *started* as an exact duplicate of ext2, then they added journalling support. A lot has changed since then(in both code bases), so they're not identical any more. Secondly, journalling does not mean that there's no fsck; it just means that it's an order of magnitute or four faster. This is because during the filesystem consistency check, we know *exactly* where to look for problems(thanks to the journal). This doesn't result in better data protection, but it does result in better availability(and hence uptime).

      Why not push ReiserFS, XFS, etc? It seems that most of these are not very well proven yet. ext2 is tried and true, kernel support is good, and the new revision adds journaling, so why not stick with ext3?

      It should be noted that XFS has been around for years. I think your basic premise is still correct, though - neither XFS(in the scope of the Linux kernel) nor ReiserFS have been tested as extensively as ext3. And since ext3's code base started as ext2's code base, it doesn't even need so much checking.

      • Secondly, journalling does not mean that there's no fsck; it just means that it's an order of magnitute or four faster. This is because during the filesystem consistency check, we know *exactly* where to look for problems(thanks to the journal). This doesn't result in better data protection, but it does result in better availability(and hence uptime).

        This isn't true. You do _not_ need to run fsck on a journal partition. A Journal does not simply say "hey the problem is here, just fix these inodes!". A Journal contains exactly what should of happened and what did happen so the inconsistance state can be repaired by "replaying" the not-yet-executed portion of the journal.

        For all intents, you don't need fsck at all. For example, RedHat 7.2 will prompt and ask if you would like to fsck a dirty partition (after the journal replay). Most people say no. If you say yes, most likely nothing will occur since everything is now consistent. It is for the paranoid.

        Ext3 is pretty nice, btw.

    • ext3fs is really just ext2fs with a journal. This is an advantage in some situations (backwards compatibility, for example). However, other journaling file systems (in particular XFS and ReiserFS) use more advanced data structures than ext2fs/ext3fs for storing metadata. For example, this means that performance of these filesystems is sometimes much, much better when you have got a huge number of files in a single directory.
      • For example, this means that performance of these filesystems is sometimes much, much better when you have got a huge number of files in a single directory.


        The key word there is "sometimes". Stephen Tweedie recently commented [iu.edu] on the Linux Kernel mailing list that resierfs is significantly faster on empty filesystems, but slows down as the filesystem approaches 90% usage (which is pretty typical for a production box).

  • Question...

    What are the individual file size limits, and overall filesystem size limits for each of the various journalled filesystems?

    I ran into the file size limit on ext2 just recently (2GB, I think it was), and I want to upgrade to something that handles larger files.

    Thanks.

    • ext2 limit graph (Score:4, Informative)

      by Anonymous Coward on Saturday November 10, 2001 @04:12AM (#2547850)
      The ext2/ext3 limit is 4 terabytes, but Linux
      device files have a 1 terabyte limit.

      http://www.cs.uml.edu/~acahalan/linux/ext2.gif

      Pay attention to the note on the right.
      That explains why apps often break at 2 GB.

  • it's really simple (Score:4, Interesting)

    by matrix0040 ( 516176 ) on Saturday November 10, 2001 @03:27AM (#2547773)
    well the best part about ext3 is if something goes wrong .. you can convert the system back to ext2 in a second.. just mount it as ext2;-) having said that .. i've been using ext3 for over a year now without any glitch. i had a 30G partition and lots of power failures .. so ext3 really eased my life and converting a current ext2 to ext3 is also pretty simple. no more backup of 30G of data ...

    • Re:it's really simple (Score:4, Funny)

      by dangermouse ( 2242 ) on Saturday November 10, 2001 @03:34AM (#2547785) Homepage
      no more backup of 30G of data ...

      You know, ext3 doesn't prevent your disk from bursting into flame or lapsing into seasonal depression and jumping off a cliff or something.

    • Re:it's really simple (Score:5, Insightful)

      by LinuxHam ( 52232 ) on Saturday November 10, 2001 @10:04AM (#2548249) Homepage Journal
      no more backup of 30G of data

      I'm hoping by this comment that you're not the same user who's Ask Slashdot just got posted, asking how to become a UNIX admin, cuz this ain't it. It's funny that you should pick that exact number too, because a close friend of mine was shifting disks around in his systems yesterday. At some point he lost track of exactly which hard drive was connected to which ribbon and which IDE port that ribbon was connected to. He ended up running a fresh install of RH7.2 over the 30GB hard drive to which he had "backed up" everything he has collected over the last five years. He called me saying he felt like he was going to throw up.

      I say "backed up" because, as an enterprise systems architect, I don't believe anything is a backup unless it takes at least a little effort to destroy the data. You can't throw a write protect tab on a hard drive. When I traded a P75 system for a 10GB hard drive with the friend above, he gave it to me with over 5GB's of his stuff on it. I backed it up to tape with Amanda, and write-protected the tape. I never thought *he* would need me to restore his data off my tape.

  • Those benchy thingies... (Score:3, Interesting)

    by trilucid ( 515316 ) <pparadis@havensystems.net> on Saturday November 10, 2001 @03:30AM (#2547778) Homepage Journal

    Anybody have any real-world benchmarks we can have a look at? I hate to sound redundant on this, but performance is a big issue for web/file servers (which is mostly what I'm running these days).

    If the "running the hell out of it" scenarios look good, I'll probably give it a shot on a production box. Actually, knowing me, I'll give it a shot anyhow, but hey... ;)

    Just as a thought, I'm operating from a starting assumption that it's *pretty much* just ext2 with journaling, but it's the overhead for the journaling that raises my eyebrows just a tad...

    Thanks for the feedback!

    • Here are some benchmarks, run on a Celeron 300A(@450MHz), 224M of RAM, on an IBM-DJNA-371350. I booted into single-user mode, with absolutely no outside connections available whatsoever. I prepared the test partition with 'dd if=/dev/zero of=/dev/hdc4'. Then I created the FS, rebooted(single-user mode, as I mentioned), mounted the FS on /mnt, then ran bonnie++ without any parameters. Here are the results:

      http://markybobdeb.sf.net/elf/tests.txt

      Kernel used was 2.4.13; first compile without ext3 patch, second compile with ext3 patch and ext3 code hardlinked.

  • Is it light on HD requirements? (Score:3, Interesting)

    by strredwolf ( 532 ) on Saturday November 10, 2001 @03:32AM (#2547783) Homepage Journal
    I'm on a laptop with a half-gig HD. No, I can't get a larger one because it's an old laptop and I don't have money to buy another. So far, I've crammed a decent install of Slack 8 with X11 onto it with about 150 Megs free on an ext2 partition.



    Reizer leaves me with 100 free



    Is this going to chew up more HD room? I'd love to find a nice, ext2-like file system to make this laptop's root.

    • Re:Is it light on HD requirements? (Score:2, Informative)

      by Anonymous Coward
      It will take a _little_ extra space. The journal is normally a file in the root of each ext3 partition which is untouchable/hidden from all but the kernel.

      The new fstools will create it for you with the -j option to mke2fs or tune2fs, but in the old days we created it with dd and passed it's inode to the kernel by a mount option - but only for the first mount.

      For my partitions of between 250Mb and 1.5Gb, I use a journal of 8Mb and have no problems. A bigger journal will allow more data to be journaled before it fills and a flush is forced, so is more efficient, but for a small disk with no big writes, a 4Mb to 8Mb journal is more than sufficient.

      BTW, the current code allow (I think) off-media journals, so you could use journal across disks, or to a battery-backed ramdisk, or an IDE disk implemented with battery backed DRAM, or SRAM.

      Unfortunately, FLASH disks would exceed their maximum-number-of-writes specification in about a year, based on a write every 30 seconds.

      astfgl@iamnota.org
    • Is this going to chew up more HD room?
      Unfortunately, yes. The journal itself takes up some room, and there's no getting around that.

      With ReiserFS, the journal size is 32MB, regardless of the partition size. Apparently [redhat.com], though, the journal size on an ext3 partition is variable, and is just 15MB by default. (Look for "Disk space" toward the end of the page.) See also the man page for tune2fs(8) with a reasonably recent version of e2fsprogs.

    • No, I can't get a larger one because it's an old laptop and I don't have money to buy another.
      You oughta pimp yourself. One evening as a naked dancer in a gay bar will gross you more than enough to buy yourself a 10 times larger drive for your laptop.

      Or if you can't get yourself to dance naked in front of drooling geezers, a few blowjobs administered to the same geezers in the john or the parking lot will do the trick.

  • GNU/ext3fs (Score:3, Funny)

    by Anonymous Coward on Saturday November 10, 2001 @03:33AM (#2547784)
    GNU/ext3fs
  • ext3 was just about the only reason I was using -ac kernels...

  • Source Forge uses ReiserFS (Score:5, Insightful)

    by brinkster ( 523812 ) on Saturday November 10, 2001 @03:45AM (#2547807)
    Not sure how new this is but a quote from someone at Source Forge on the ReiserFS site.

    http://ftp.sourceforge.net/ has 850GB storage, half of which is reiserfs, half is ext2. Both filesystems have been running flawlessly for > 4 months of production (actually longer, but wasn't reiserfs before). That server pushes between 15Mbit and 50Mbit/sec, and pulls/syncs about 2-5Mbit/sec, 24x7. reiserfs also powers the CVS tree filesystem for cvs-mirror.mozilla.org (also tokyojoe.sourceforge.net), which is the one and only anonymous CVS checkout point for mozilla. That server has run flawlessly under very heavy load since its birth. I don't get involved in kernel politics, but as a production filesystem, reiserfs is ok in my book.

    • Not sure who that quote came from, but anyone claiming cvs-mirror.mozilla.org has run "flawlessly" is full of it. While it's problems may not be filesystem related, the box ISN'T perfect.
  • Well, I don't know about that. I've been using ReiserFS [namesys.com] since about 2.2.17 or 2.2.18, and it's worked great. It was officially integrated into the kernel in 2.4.1 [kernel.org] (at the end of January this year), and distributions started incorporating it soon after. (Actually, before that, if I'm not mistaken. I was installing my work laptop last November, and the then-current version of SuSE supported creating ReiserFS partitions during the install even then. Wound up going back to Debian, though.)

    So journalling's been available to the masses for a while now. Or maybe Michael meant ease of converting for the installed base?

    Now if only the damn preemptible kernel [tech9.net] patch would make it in. Unfortunately, it looks like that's going to wait until 2.4.5 [zork.net]. *sigh*...

    • Linus on preemptible kernel (and Tweedie on ext3) (Score:5, Informative)

      by kingdon ( 220100 ) on Saturday November 10, 2001 @04:12AM (#2547848) Homepage

      Someone asked Linus about the preemptible kernel patches (and latency in general) at the Annual Linux Showcase on Thursday night. The thing about the preemptible kernel is that it is only for uniprocessor - SMP kernels aren't preemptible. So unless you want the SMP case to be capable of tying up a processor for "too long" at a time, then you need to re-do each bit of code which is capable of long latencies anyway. The other thing which came up is that responsiveness of the system improved quite a bit recently with VM fixes (2.4.14 was the improved version, I think). It was a matter of the VM queueing up too much I/O (and the drivers trying to throttle it, instead of just throttling it all in the VM - or something like that). The preemptible kernel won't solve that kind of problem - although it may change/mask the symptoms enough to make it a bit hard to be sure where a problem is.

      Oh, and to bring things back to ext3, Steven Tweedie was also there and made a number of comments about ext3. He has been fairly busy/nervous lately as ext3 just got into the hands of Lots Of(TM) users (when it shipped with Red Hat 7.2). The most serious problem I remember him talking about was that the 7.2 installer had a box marked "upgrade my ext2 to ext3" and one marked "makefs the filesystem" (or something like that), and some people were checking both - which would create a nice new empty filesystem in place of the one which was being "upgraded". But of course that is just user error plus a confusing installer, not a kernel problem. Most of the things which looked like ext3 kernel problems seem to be something else, as far as Steven has been able to tell so far.

  • Re: (Score:2, Offtopic)

    by account_deleted ( 4530225 )
    Comment removed based on user account deletion

    • ReiserFS kills interactive performance (Score:2, Interesting)

      by Anonymous Coward
      I've been using ReiserFS since about a month after it went into the standard 2.4 kernel tree, since I wanted a journalling filesystem. At first I just used it for /usr, and it worked great. There was a noticable performance increase accessing large directories (like /usr/share/doc), and it saved some space. A few months later I converted /home. It works OK normally, but when copying large files, the system becomes entirely unusable. The mouse pointer lags noticeably (it jumps across the screen in 100-pixel intervals), my 4-second XMMS buffer is emptied and my music stops playing, and the system load jumps to somewhere between 3 and 5. This is on a 1GHz P3, and DMA is on. I had the same problem on my 700MHz P3, with a different motherboard, but I never had these problems with ext2.

      The problem is that writers starve readers on ReiserFS. When writing a lot of data (for example, copying an MP3 album or a movie), no processes will be able to read from that filesystem. It's a known problem in the ReiserFS FAQ, but they really downplay it's severity. If you regularly work with large files, or copy large groups of files (more than ~50MB), stay away from ReiserFS.

    • I have been using ResierFS for a few months now, and for the most part, it has worked well.

      But the lack of a fsck is inexcusable. I have has a couple of "events" which might have corrupted a filesystem (my fault, not resierfs'), but had no way to check. Once, I went through my partitions one by one, copied them to a temp partition, mkfs'ed them, and copied them back. I put up with it because it was a pain in the butt to switch. Now that ext3 is in a Linus kernel, I am seriously considering running some tests, and converting back.
  • I have nothing against the ext3 filesystem or the new virtual memory patch but Linus needs to stop adding these relatively radical changes into the so called stable kernel reserved only for drivers and bug fixes. The issue is not that big for most hackers reading this but alot of us run Linux on mission critical servers that we bet our jobs on. Even before the radical kernel patches, all the newer kernels had big-time showstopper bugs. Many admins even run the old 2.2 kernel to avoid unnecessary problems. I have been running 2.4 and had no problems yet luckily. However I really do not know if I can recommend Linux as a server OS anymore. I want stability and Freebsd and Solaris seems to meet my needs alot more. Hopefully this madness will stop soon. We all love to bash Microsoft for releasing buggy service packs for NT that have not been tested thoroughly but there seems to be no real testing with Linux kernel patches. Freebsd conquered this problem by having 2 development teams. One for the stable branch and one for the development branch. No radical changes are allowed in the stable branch and the stable branch must go under lots of testing to be approved to be released as stable. I now know why BSD hackers love there development model. Cutting edge is great for some users but please do not include it in the kernel where a lot of people count on it for servers and mission critical applications.

    • Uh, No. He's Adding Support, Not Replacing ext2 (Score:4, Insightful)

      by Lethyos ( 408045 ) on Saturday November 10, 2001 @04:40AM (#2547902) Journal
      Okay, if you have a set A with N elements, and you add an element to the set such that set A now has N+1 elements... well, that doesn't change the original 0 through N elements.

      Your complaint can be applied to the case of adding driver support to an existing kernel. You see, in the life of a kernel, time passes. As time passes, new hardware, software, algorithms, etc. come out. In order for us to keep modern, we have to add new things to the existing set. You're just... silly.

      Going back to my original statement, the new virtual memory subsystem wasn't an addition. He was removing an element from the set and replacing it with something different. That could be argued as bad, but in practical terms it ended up perfectly fine.

      Furthermore, if you had done any homework, you'd have realized that ext3 is built using hooks that have been available in ext2 for years. Technically speaking, ext3 is as stable as ext2 because the fs can still function as ext2 if ext3 support goes away or breaks.

      So stop bitching about support for new things being added to the kernel. We could only be lucky if new features were added faster. At the very least, stop dumping FUD on us. Your alias is so very appropriate in light of your post.
      • In the case of ext3, I actually agree with what is otherwise the greatest example of weasel-wording since the Evangelists excusing everything Apple does.

        ext2 does not synchronously write metadata -- a power fail can hose everything. Thus I consider ext3 a bugfix on ext2, albeit a somewhat radical one. Same goes for the AA VM, a radical bugfix on a broken VM that should have been a show-stopper for 2.4 in the first place.

        Otherwise, you're pretty much the kind of support Linux frankly doesn't need. Keep giving people attitude, soon enough you won't have to anymore, because they'll turn elsewhere.
    • No radical changes are allowed in the stable branch and the stable branch must go under lots of testing to be approved to be released as stable. I now know why BSD hackers love there development model. Cutting edge is great for some users but please do not include it in the kernel where a lot of people count on it for servers and mission critical applications.
      Yeah, the Linux equivalent is called Debian Linux [debian.org]. You can run the main or stable branch of the distro, and while you give up bleeding bloody edge software, you gain stability and reliability unheard of in Redhat land. There is more to this world than Redhat based Linux distros (Debian, etc...). Just as there is more to this world than Linux (BSDs, etc...) The software is free and runs on nearly everything, so you have no excuse for not giving alternatives a try.
    • Linus needs to stop adding these relatively radical changes into the so called stable kernel reserved only for drivers and bug fixes.

      Think of ext3 as "only a driver" -- which in your book is OK for a stable kernel. In terms of how much the code disturbs the rest of the kernel if you don't compile it in -- it really doesn't, just like a driver.

      The VM change in 2.4.10 -- there I agree with you. (As does Linus, apparently, as he later admitted.)

    • A) No one is forcing you to upgrade. If you are throwing the bleeding edge onto Prod servers you deserve what you get. That doesn't just apply to Linux, it applies to Solaris, AIX, HP-UX, Windoze and everything else. Get a clue.
      B) At least Linus isn't terrified of making changes to the existing code base and fixing inherent problems, regardless of his testing base. I just ran into an issue on Solaris where as we had a middleware daemon (TIBCO Rendezvous) which hit upon a rather serious flaw in 32-bit Solaris where it could not resolve more than 256 calls to alias a port/service. At 257 the call to resolve a service alias would just fail. We talked to Sun about it and they said they knew it was an issue an refused to change it (ever) cause it would require them to change a foundation C struct that might break a bunch of apps. I understand Sun's viewpoint, but they have taken the 'safe' approach where they are locked into code limitations of the past. Great, so I get stuck with un-documented bug-crap forever.
      C) Linus is the visionary, not the tester. If you don't trust RedHat or others to test the upgrades, and you don't have the desire/bandwidth to do it yourself, then you either shouldn't be running Linux or shouldn't be considering upgrades.
      • A) No one is forcing you to upgrade. If you are throwing the bleeding edge onto Prod servers you deserve what you get. That doesn't just apply to Linux, it applies to Solaris, AIX, HP-UX, Windoze and everything else. Get a clue.

        True, as long as the kernel is labeled "bleeding edge". As far as I understood, that was what the even/odd numbering was for: 2.3.x, 2.5.x unstable, but 2.2.x and 2.4.x stable. "Even" kernels are meant to only receive bugfixes or rather peripheral additions (new drivers, yes, and also new filesystems), but no fundamental changes (new VM...).

        If this had happened during 2.3.x, nobody would have complained. People even don't expect the 2.3.x kernels to compile... After all, this is what the development branch is for. But on the other hand, such changes have no place in the so-called stable branch.

  • Well, when I installed slackware 8, I pulled a few tricks out of my hat to use ReiserFS. So far, it's been flawless for my rather normal needs. The few times I've gone down, I came back up with no problems.

    So, mark one vote of confidence for reiser.

  • ext3 and quotas.... (Score:4, Interesting)

    by weave ( 48069 ) on Saturday November 10, 2001 @06:36AM (#2548039) Journal
    I'm trying to decide whether or not to convert a production system I manage that has 16,000 user accounts connected to a 1 terabyte EMC SAN. I've done a lot of searches and turned up some troubling posts [google.com] about ext3 when it comes to using it with journaling and quotas turned on.

    It's like what's worse, dealing with a fscks that seems to take hours or increasing the risks of more crashes but at least you get back up faster. I can't live without quotas either. Can you imagine a student in a lab with a 10 Mbps connection to the Internet and a few hundred gigabytes of writable space? :)

    It's starting to look like I can't have my cake and eat it too. :(

    I'm glad Linus is blessing it. Hopefully the issues will be resolved soon. Until then, maybe redhat jumped the gun including it in their distro...

    • Re:ext3 and quotas.... (Score:3, Informative)

      by selmer ( 37218 )
      It looks like there are still some quota-problems with the Linus-kernels, check this post [redhat.com] on the ext3 user-list, in which which Andrew Morton says that there are no known quota-problems with the ac-kernels but that he wants to test a bit more on the Linus-kernel as it used to cause deadlocks.
    • Why not use XFS. Sure its doesn't have holy penguin pee all over it, but I haven't heard about any stability problems with it, and its support for pro level servers (even on Linux) seems to be quite good.

  • What about 2.5.x? (Score:2, Informative)

    by Cryptnotic ( 154382 )
    Shouldn't this REALLY REALLY be in Linux-2.5.x? What ever happened to the old mantra "odd numbers, development, new features; even numbers, stable, bug fixes"? Has Linus forgotten? First, completely changing the virtual memory system in 2.4.10, now this.


    Cryptnotic

  • Tip: Root partition not being mounted ext3? (Score:4, Informative)

    by Spoing ( 152917 ) on Saturday November 10, 2001 @09:22AM (#2548199) Homepage
    If you're converting from ext2 to ext3, update /fstab so that 'auto' is used instead of either 'ext2' or(!)'ext3'. Auto makes it easy to dynamically switch to a kernel that doesn't support ext3.

    Unfortunately, if your file system tools aren't upto date, your root partition won't be mounted ext3. A quick check to see if everything worked is to look at the output from either df or /proc/mounts like this;

    1. df -T

    In the second column, it should report the filesystem type of each mounted partition. If you don't see / , you should upgrade fileutils.

    1. cat /proc/mounts

    This is basically how your fstab is currently interpreted, as recorded in /etc/mtab.

    If either of these look wrong, check the kernel sources for Documentation/Changes, and verify that you are using the supporting program versions mentioned in the Current Minimal Requirements section.

    • Actually, I've found that putting ext3 (in /etc/fstab) with no ext3 support will automagically mount as ext2. I've also heard that having something like ext3,ext2 will work, but I've never tried it.

      Oh, and to check if you have ext3 you can also use tune2fs -l /dev/blah and look for the has_journal flag in the Filesystem features field.
      For your root filesystem, you may also see something like VFS: Mounted root (ext3 filesystem).

      Andrew.
    • If you mount all your filesystems as "auto", and you use slocate, then be sure to edit the small file /etc/updatedb.conf and remove "auto" from the list of PRUNEFS types.

      Otherwise updatedb will ignore your "auto" filesystems (i.e., your whole system) and the slocate database will be empty.

  • Are there any disk array controllers or other storage devices that do FS-independant journaling at the block level?

    It'd be an interesting way of doing backups -- instead of restoring from tape, you could get the disk controller to back out changes to a specific timestamp.

    I'm sure there are some gotchas -- without knowledge of the filesystem, a specific hardware level transaction may not have complete filesystem level coherency, for one. And it may take a lot of disk to keep a log of any decent duration.

    But it still seems like an interesting way to accomplish some kind of fault tolerance for any OS.
    • Uhhm, there is no such thing as "hardware journalling". It's an oxymoron. By definition, journalling is file system-dependent.

      As for restoring changes with specific time stamp, there are three problems with that:

      1. The amount of storage space required would grow exponentially (depending on how fine-grained the timestep is).

      2. The speed would go down the toilet (again, depending on the timestep).

      3. It would still be file system-dependent.

      FYI, the NetApp filers have the "snapshot" feature which allows you to recover deleted files. But note that it works only for deleted files. It does not keep track of modifications. So that's really trivial (something similar to "recycle bin" in windows), and could easily be implemented in any file system. Speaking of which, I'm surprised it hasn't been done yet.
      • Uhhm, there is no such thing as "hardware journalling". It's an oxymoron. By definition, journalling is file system-dependent.

        Why is that? A simple version of what I'm thinking of would be a disk controller with two disks attached. One is your real disk the other is the journal disk. Every block level operation would be written twice, once to the real disk, and one to the transaction log with a timestamp.

        Clearly any reasonably busy filesystem would require a lot of storage to maintain the transaction log (and maybe that's what would make this impractical for high-volume systems), but how many systems with 100G of disk modify all 100G every day? 100G of disk with 10G of modification per day could be journaled for at least 9 days with an equivilent journal disk.

        Speed is a non-issue, IMHO. Any reasonably modern disk array controller can handle mirrored writes with no problem, and this is not much different from mirroring.

        Many SAN storage systems have the ability to make snapshot copies of individual LUNs, I was told by one vendor that they were working on the ability to make incremental copies of a snapshot.

        Journaling a LUN seems like a logical extension of this ability, and a way to provide fault tolerance.

  • Problem with Journaling FS (Score:3, Funny)

    by tie_guy_matt ( 176397 ) on Saturday November 10, 2001 @10:47AM (#2548327)
    When I first switched to Reiser I had this habit of just turning off the power to my box every few minutes just because I could. No good could come from this. Hopefully as more people switch to journaling FS they will have more self control than I had. Anybody else do the same thing? It is so addictive! Must resist turning off box after I post this...
    • Red Hat 7.2's release notes on ext3:

      Please keep in mind that even a journaling file system can be damaged by power loss. When a system loses power, that system's behavior is
      undefined. For example, memory contents can decay (become randomly corrupt) as the contents are copied to a hard drive running on the
      last bit of power. This is a fundamentally different situation from the more defined sequence of events caused by pressing the system's "reset" button while the system is running. In addition, IDE hard drives do not provide all of the write order guarantees that SCSI drives do.
  • Now Slashdot is posting pre versions of the kernel.

    2.4.15pre2 is out!!!
  • I see post after post reporting gleefully that people now can just pop off the power, believing that journaling will save their data from harm.

    It's not true.

    If you have only SCSI disks, it may be true, if your disks are from a very reputable manufacturer. (They are few, and charge more.)

    If you have IDE disks, it is almost certainly false. IDE disks report data successfully written to disk when it is still only in on-board RAM buffers. Even when told not to, they often do it anyway. (Lying results in better benchmark scores.)

    If you have IDE disks, journaling will help protect you against various lockups and crashes, but if the disk is active when the power goes out, all bets are off. If you think you didn't lose data, maybe you got lucky, or maybe you just haven't noticed your losses yet.

    The reason IDE disks are cheaper than SCSI is that the people who buy IDE disks have much, much lower quality standards. To compete, the manufacturers are forced to deliver lower quality. If you care about reliability, buy SCSI (or fiber-channel, or ...).

    If you use IDE, watch that power switch, and keep current backups. If you maintain critical data, invest in a UPS. Journaling is not a substitute for a UPS, it's just a time saver.

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