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Data Storage Software Linux

On the State of Linux File Systems 319

Posted by kdawson
from the here-hold-this-for-me dept.
kev009 writes to recommend his editorial overview of the past, present and future of Linux file systems: ext2, ext3, ReiserFS, XFS, JFS, Reiser4, ext4, Btrfs, and Tux3. "In hindsight it seems somewhat tragic that JFS or even XFS didn't gain the traction that ext3 did to pull us through the 'classic' era, but ext3 has proven very reliable and has received consistent care and feeding to keep it performing decently. ... With ext4 coming out in kernel 2.6.28, we should have a nice holdover until Btrfs or Tux3 begin to stabilize. The Btrfs developers have been working on a development sprint and it is likely that the code will be merged into Linus's kernel within the next cycle or two."
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On the State of Linux File Systems

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  • by tytso (63275) * on Saturday November 29, 2008 @04:49PM (#25927531) Homepage

    The article states that ext4 was a Bull project; and that is not correct.

    The Bull developers are one of the companies involved with the ext4 development, but certainly by no means were they the primary contributers. A number of the key ext4 advancements, especially the extents work, was pioneered by the Clusterfs folks, who used it in production for their Lustre filesystem (Lustre is a cluster filesystem that used ext3 with enhancements which they supported commercially as an open source product); a number of their enhancements went on to become adopted as part of ext4. I was the e2fsprogs maintainer, and especially in the last year, as the most experienced upstream kernel developer have been responsible for patch quality assurance and pushing the patches upstream. Eric Sandeen from Red Hat did a lot of work making sure everything was put together well for a distribution to use (there are lots of miscellaneous pieces for full filesystem support by a distribution, such as grub support, etc.). Mingming Cao form IBM did a lot of coordination work, and was responsible for putting together some of the OLS ext4 papers. Kawai-san from Hitachi supplied a number of critical patches to make sure we handled disk errors robuestly; some folks from Fujitsu have been working on the online defragmentation support. Aneesh Kumar from IBM wrote the 128->256 inode migration code, as well as doing a lot of the fixups on the delayed allocation code in the kernel. Val Henson from Red Hat has been working on the 64-bit support for e2fsprogs in the kernel. So there were a lot of people, from a lot of different companies, all helping out. And that is one of the huge strengths of ext4; that we have a large developer base, from many different companies. I believe that this wide base of developer is support is one of the reasons why ext3 was more succesful, than say, JFS or XFS, which had a much smaller base of developers, that were primarily from a single employer.

    • by tytso (63275) * on Saturday November 29, 2008 @05:04PM (#25927637) Homepage

      Oh, by the way... forgot to mention. If you are looking for benchmarks, there are some very good ones done by Steven Pratt, who does this sort of thing for a living at IBM. They were intended to be in support of the btrfs filesystem, which is why the URL is http://btrfs.boxacle.net/ [boxacle.net]. The benchmarks were done in a scrupulously fair way; the exact hardware and software configurations used are given, and multiple workloads are described, and the filesystems are measured multiple times against multiple workloads. One interesting thing from these benchmarks is that sometimes one filesystem will do better at one workload and at one setting, but then be disastrously worse at another workload and/or configuration. This is why if you want to do a fair comparison of filesystems, it is very difficult in the extreme to really do things right. You have to do multiple benchmarks, multiple workloads, multiple hardware configurations, because if you only pick one filesystem benchmark result, you can almost always make your filesystem come out the winner. As a result, many benchmarking attempts are very misleading, because they are often done by a filesystem developer who consciously or unconsciously, wants their filesystem to come out on top, and there are many ways of manipulating the choice of benchmark or benchmark configuration in order to make sure this happens.

      As it happens, Steven's day job as a performance and tuning expert is to do this sort of benchmarking, but he is not a filesystem developer himself. And it should also be noted that although some of the BTRFS numbers shown in his benchmarks are not very good, btrfs is a filesystem under development, which hasn't been tuned yet. There's a reason why I try to stress the fact that it takes a long time and a lot of hard work to make a reliable, high performance filesystem. Support from a good performance/benchmarking team really helps.

      • by sjames (1099)

        As a result, many benchmarking attempts are very misleading, because they are often done by a filesystem developer who consciously or unconsciously, wants their filesystem to come out on top, and there are many ways of manipulating the choice of benchmark or benchmark configuration in order to make sure this happens.

        The other side of the coin can come up as well. If you develop and test everything on one platform with one test workload, it's easy to unintentionally make it highly optimal for that exact setup and terrible elsewhere.

      • Re: (Score:3, Interesting)

        by grimJester (890090)
        As a result, many benchmarking attempts are very misleading, because they are often done by a filesystem developer who consciously or unconsciously, wants their filesystem to come out on top, and there are many ways of manipulating the choice of benchmark or benchmark configuration in order to make sure this happens.

        Wouldn't it be logical to assume a filesystem developer has an idea on what the workload and hardware will be like _before_ writing his filesystem, then picking a benchmark that suits his idea
        • by droopycom (470921)

          I dont think it would be logical at all.

          First, It would mean that each workload would require a different filesystem design.

          Then it would also mean that you dont need synthetic benchmarks at all, just a run the expected workload as your "benchmark".

        • Wouldn't it be logical to assume a filesystem developer has an idea on what the workload and hardware will be like _before_ writing his filesystem, then picking a benchmark that suits his ideas on what a filesystem is supposed to do?

          No, that would be illogical, unless again they were trying to craft bullshit benchmarks. The developer does not know how I will use the filesystem, and so any such benchmark is not useful to me. I also want to know how well the filesystem will perform if I have to perform some new task on it.

    • Re: (Score:2, Insightful)

      by transami (202700)

      Repeato ad absurdium...

      All these fancy features, but we are still using filename extensions (eg. .zip) to specify data types.

      Did OOP even happen?

      • Re: (Score:2, Insightful)

        by dougisfunny (1200171)

        What do you want to specify the data type?

        Some non-human readable meta data? If someone sends you a Not-a-virus.txt in an email attachment, what kind of file is it? An executable a funny story? How would you know?

      • Oh, who does that?
        My OS certainly doesn't care.

      • by siride (974284)

        There are extended attributes and magic numbers. Some file managers seem to make limited use of these. I guess the problem with extended attributes is that they aren't guaranteed to be transferable along with the file when you, e.g., upload the file to a website, or transfer it to another computer. Only the main stream of a file is guaranteed to be transfered.

        But make no mistake, the filesystem fully supports this kind of information. We just don't seem to make much use of it right now.

      • by ChameleonDave (1041178) on Sunday November 30, 2008 @02:46AM (#25930989) Homepage

        Repeato ad absurdium...

        What is that gibberish supposed to mean? Christ, I hate mock-Latin. If you want a fancy-sounding term referring to repeating something again and again, use ad nauseam.

  • Lightweight (Score:5, Insightful)

    by postbigbang (761081) on Saturday November 29, 2008 @04:51PM (#25927551)

    A cute FA in some ways, but bereft of content. Wish there was something to see here, like comparisons regarding integrity, access costs, evolution from JFS and Andrews journaled FS, etc. No real meat (with apologies to the vegetarians out there). Just a lightweight historical analysis with some glib suggestions of current adaptations.

  • ZFS!! (Score:3, Interesting)

    by Anonymous Coward on Saturday November 29, 2008 @05:04PM (#25927639)

    What Sun needs to do is release ZFS under a proper license so we can finally have 1 unified filesystem. Yes, we can use it under FUSE, but this brings unnecessary overhead and problems. It will be nice when we can transport disks around, similar to fat(32), and not have to worry about whether another OS will be able to read it or not. On top of that, CRC block checksumming, high performance, smb/nfs/iscsi support integrated, Volume AND partition manager.

    Come on Sun! Are you listening??

    • Re:ZFS!! (Score:5, Funny)

      by TheRaven64 (641858) on Saturday November 29, 2008 @05:15PM (#25927709) Journal
      Sun has released it under a proper license and we can finally have 1 unified filesystem. The 'we' in this case being Solaris, Mac OS X, and FreeBSD users, of course.
      • by Gazzonyx (982402) on Saturday November 29, 2008 @05:55PM (#25927959)
        Never have I been so happy and so angry in such a short period of time. I salute you, yet still shake my fist angrily in your general direction.
    • Re: (Score:2, Insightful)

      by Anonymous Coward

      Shouldn't ext2 already be that unified file system? Oh, that's right -- GPL prevents anybody else from using. Just like GPL prevents ZFS code from being used in Linux. Looks like the problem is the GPL.

      • Re:ZFS!! (Score:5, Insightful)

        by harry666t (1062422) <[harry666t] [at] [gmail.com]> on Saturday November 29, 2008 @05:47PM (#25927907)
        You can have an alternative implementation of ext2 that wouldn't have to use GPL'd code from Linux. I saw ext2/3 drivers for Windows and I'm pretty sure that at least some of the non-GPL OSs out there (Mac? BSDs? Solaris?) can read/write ext2.

        However, you can't reimplement ZFS under any other license (CDDL is licensing some of the patents that cover the ZFS only to the users of the original implementation or its derivatives). I'd say it's *BOTH* GPL's and CDDL's fault (what's more, Sun chose CDDL exactly because it's GPL-incompatible).
        • The fact that I can't use Sun's software how I want is a problem with GPL how?

          • Re:ZFS!! (Score:4, Insightful)

            by beelsebob (529313) on Saturday November 29, 2008 @08:32PM (#25928837)

            Because Sun are licensing the software for you under a free and open source software license. The only thing stopping you from using it is that it's a license that doesn't agree with the ideology of the "all FOSS must be viral" GPL guys, and thus can't be used with GPLed software. There's plenty of non-GPLed projects that are happily getting on and using ZFS, but GPL guys can't. I'd say that makes it pretty obvious what the problem is.

            • by rubycodez (864176)

              yes, problem is Sun's stupid licensing once again preventing them from gaining wide adoption or turning a profit with software (see also Java). Sun is losing money, too little too late in the direction of open source. bye bye Sun.

      • Re:ZFS!! (Score:5, Interesting)

        by dokebi (624663) on Saturday November 29, 2008 @06:00PM (#25927991)

        UFS (of BSDs) is under the most liberal license possible, yet it's definitely not the most widely used. FAT32 is patented by MS, and it is the most widely used. So, do you still think the problem is GPL?

    • Re:ZFS!! (Score:5, Insightful)

      by diegocgteleline.es (653730) on Saturday November 29, 2008 @05:53PM (#25927947)

      ZFS has redefined the way future filesystems are going to be designed. But there is no way that it's going to be the "last" filesystem.

      As shocking as it may seem to those who have drunk the marketing kool aid, we'll see more filesystems. Filesystem research is as alive as it always was. They'll try to copy the good ideas of ZFS and they will try to avoid the disadvantages (which every software has). So you are never going to have "1 unified filesystem". It's never going to happen. And it's a good thing.

      • Re: (Score:2, Redundant)

        by isorox (205688)

        They'll try to copy the good ideas of ZFS and they will try to avoid the disadvantages (which every software has). So you are never going to have "1 unified filesystem". It's never going to happen. And it's a good thing.

        One thing I'd really like is using free space on a raidz(2) as a spare disk.

        Imagine the following
        10 1TB disks in a raid5/raidz, giving 9TB of space. You are currently using 7TB, this peaks to 8.5TB at the weekend while backups are staged (or whatever).

        During the week you have unused space. T

        • Another feature would be automatically copying of frequently accessed files -- if a certain bunch of files on a website becomes popular, they would be transparently copied across the spindles to increase access time.

          Doesn't Sun's new ZFS-based "open storage" hardware do this already to some extent? It automatically moves the most accessed files onto the solid state drives to speed things up.

        • Re:ZFS!! (Score:5, Interesting)

          by Kent Recal (714863) on Saturday November 29, 2008 @07:59PM (#25928641)

          I hear you and I'm sure the filesystem developers have the same ideas in their heads.
          The problem is that there are some really hard problems involved with these things.

          In the end everybody wants basically the same thing: A volume that we can write files to.
          This volume should live on a pool of physical disks to which we can add and remove disks at will and during runtime.

          The unused space should always be used for redundancy, so when our volume is 50% full then we'd expect that 50% of the disks (no matter which) can safely fail at any time without data loss.

          Furthermore we don't really want to care about any of these things. We just want to push physical disks into our server, or pull them, and the pool should grow/shrink automagically.
          And ofcourse we want to always be able to split a pool into more volumes, as long as there's free space in the pool we're splitting from. Ideally without losing redundancy in the process.

          We want all these things and on top we want maximum IOPS and maximum linear read/write performance in any situation. Oh, and we won't really be happy until a pool can span multiple physical machines (that will auto re-sync after a network split and work-as-expected over really slow and unrealiable networks), too.

          ZFS is a huge step forward in many of these regards and there's a whole industry built solely around these problems.
          Only time will tell which of these goals (and the ones that I omitted here) can really be achieved and how many of them can be addressed in a single filesystem.

      • As shocking as it may seem to those who have drunk the marketing kool aid

        For the love of God, can we please stop using that metaphor [wikipedia.org]? When you think of all that it implies, it's literally sickening...

        Filesystem advocacy discussions rarely (if ever) bring up mention of the Holocaust or 9/11. How is it any more appropriate to draw comparisons to the largest mass-suicide in modern history?

        • Re: (Score:3, Insightful)

          by Da Masta (238687)

          Get a grip.

          The people of Jonestown CHOSE their fate. They weren't systematically hunted down for their race nor were they killed for being in the wrong city in the wrong building at the wrong time. Everyone in that cult CHOSE to give up their worldly belongings, uproot their lives to Guyana, AND drink the cyanide laced juice (not actually kool-aid) for "revolutionary" causes.

          As long as propaganda and rhetoric have their effects, we should ABSOLUTELY continue to use that metaphor as a reminder against blind

    • Re: (Score:2, Insightful)

      by jopsen (885607)

      It will be nice when we can transport disks around, similar to fat(32), and not have to worry about whether another OS will be able to read it or not.

      I'm no filesystem expert... But I think different filesystems for different purposes is a good idea... Do you want to use ZFS on a flash disk or external harddrive... (the ladder might make a little sense).

      Generally I don't get all the fuss about ZFS... Okay, it's cool that we'll need more energy to reach it's limits than needed to boil this oceans...

      smb/nfs/iscsi support integrated, Volume AND partition manager.

      Yes, that's cool... But why does it need to be *in* the filesystem???
      I'm not expert but AFAIK we've got LVM for volume management, and we can run any filesy

      • Re:ZFS!! (Score:5, Interesting)

        by atrus (73476) <atrus@@@atrustrivalie...org> on Saturday November 29, 2008 @06:26PM (#25928141) Homepage
        Because having a block based filesystem that has no notion of what the underlying storage is "dumb". ZFS fixes those problems.

        Want to create a new filesystem in ZFS? Sure, no problem. You don't even need to specify a size, it will use whatever space the storage pool has available, no pre-allocation needed. How about removing one? Ok, its removed. Yes, it only took a second to do that. A traditional LVM + FS system can't do that - you need to resize, move, and tweak filesystems when doing any of the above operations - time consuming and limited.

        And if you're asking why you'd want to create and remove filesystems on the fly, there is one word for that: snapshots. Its quite feasible to generate snapshots many times per day for a ZFS backed fileserver (or even database server). Someone created a file at 9am and then accidentally nuked it before lunch? Don't worry, its still present in the 10am and 11am snapshots. All online, instantly available.

        • There's no reason (IMHO) not to expose the LVM API to the filesystem layer of course, allowing the filesystem to make these determinations intelligently as ZFS dos.

      • Re:ZFS!! (Score:5, Interesting)

        by ArbitraryConstant (763964) on Saturday November 29, 2008 @06:43PM (#25928233) Homepage

        > But hey maybe I'm missing something, why not improve or create a replacement for LVM instead of including volume management in the filesystem?

        Maybe. But it would be a lot harder.

        Think about LVM snapshots for example. LVM allocates a chunk of the disk for your filesystem, and then a chunk of disk for your snapshot. When something changes in the parent filesystem, the original contents of that block are first copied to the snapshot. But if you've got two snapshots, it has to be copied to two places, and each snapshot needs its own space to store the original data. Because ZFS/BTRFS/etc are unified, they can keep the original data for any number of snapshots by the simple expedient of leaving it alone and writing the new data someplace new.

        LVMs can grow/shrink filesystems, but filesystems deal with this somewhat grudgingly. LVM lacks a way to handle dynamic allocation of blocks to filesystems in such a way that they can give them back dynamically when they're not using them. ZFS/BTRFS/etc can do this completely on the fly. LVMs rely on an underlying RAID layer to handle data integrity, but most RAID doesn't do this very well. BTRFS is getting a feature that allows it to handle seeky metadata differently than data (eg, use an SSD as a fast index into slow but large disks).

        It is conceivable that an advanced volume manager could be created that does all these things and all the rest (eg checksumming) just as well... but I think the key point is that this isn't something you can do without a *much* richer API for filesystems talking to block devices. They'd need to be able to free up blocks they don't need anymore, and have a way to handle fragmentation when both the filesystem and the volume manager would try to allocate blocks efficiently. They'd need substantially improved RAID implementations, or they'd need to bring the checksumming into the volume manager. I'm not saying it can't be done, but doing it as well as ZFS/BTRFS/etc when you're trying to preserve layering would be very tough. At a minimum you'd need new or substantially updated filesystems and a new volume manager of comparable complexity to ZFS/BTRFS/etc. I understand the preference for a layered approach, but I just don't think it's competitive here.

        • Re: (Score:3, Informative)

          You just have to draw the layers differently.

          I've repeatedly proposed something, only to find that ZFS already implements it: Define one layer which is solely responsible for storing your bare primitives, like a sequence of data. It is the FS-level equivalent of malloc/free.

          Then, implement everything else on top of that layer. Databases could sit directly on the layer -- no reason they need to pretend to create files. Filesystems would sit on that layer, implementing structures like directories and POSIX fi

    • by Jesus_666 (702802)
      Actually, if you want a filesystem usable by everyone it will definitely have to come from Microsoft. MS is not going to adopt someone else's FS unless they really have to, so the only serious contenders are FAT32, NTFS and exFAT (things like UDF are highly unlikely as Microsoft probably won't support it for anything but DVD images).

      FAT32 is the current portability king. However, it's also old and extremely limited and people stopped liking it half a decade ago.

      NTFS works... kinda. For example, you can
      • Actually, if you want a filesystem usable by everyone it will definitely have to come from Microsoft.

        It doesn't much matter whether they cooperate. Even if they insist that the Windows boot device continue to be NTFS, there's a standard way to write filesystem drivers for Windows (ext2 is already supported), and it's easy to put just about everything except Windows itself on another partition, if we have to. (Which we probably won't -- we could even slipstream it in.)

        So, we can force the issue.

        And suppose I have a portable hard drive, which I want to make sure is readable everywhere -- all I have to do is

        • by Jesus_666 (702802)

          And suppose I have a portable hard drive, which I want to make sure is readable everywhere -- all I have to do is make a separate FAT32 partition with all the relevant software on it for Windows and OS X to read the other partition.

          Tried it, didn't work. In order to do anything meaningful with a non-FAT/NTFS drive under Windows you need to install an IFS. Few people are going to let you install some random driver on their notebook just to access your USB drive. That's also the reason why MacDrive and ext2-I

      • Re: (Score:2, Informative)

        by szaka (1061180)
        ntfs-3g is hardly a default package in most distros

        Actually it's available for over 190 distributions [ntfs-3g.org] and it's the default one the most popular ones, e.g. Ubuntu, openSUSE, Fedora, Mandriva, Slackware, etc. Btw, thanks to FUSE, NTFS-3G also works on FreeBSD, NetBSD, OpenSolaris, OS X and some others (more in the way).

    • by Sentry21 (8183)

      What most Linux users seem not to realize is that Sun has done their part. They've released their code under an OSI-approved license. ZFS (and dtrace) are open-source. Linux could implement them - except the GPL prevents it.

      Linux (thanks to the GPL) is the one saying 'I'm not going to play unless we can use my ball', which is fine because the rest of us are having a good time regardless.

      I'd love to see someone port ZFS to Linux and distribute it as a set of patches for people to download and apply to their

    • Or you can change your license so it works with Suns License. Yea you can change too it is probably just as easy or difficult for you to do it as it is for Sun to do it.

  • by bboxman (1342573) on Saturday November 29, 2008 @05:18PM (#25927725)

    Just my 2 bits. As a user of Linux in a software/algorithm context, my personal beefs with ext3 / the current kernel line are:

    1) IO priority isn't linked to to process priority, or at least, not in a decent manner. it is all too easy to lock up the system with one process that is IO heavy (or a multiple of these) -- hurting even high priority processes. As the IO call is handled by a system level (handling buffering, etc.) -- it garners a relatively high priority (possibly falling under the RT scheduler) and as a result IO heavy processes can choke other processes.

    2) ext3+nfs simply sucks with very large amount of files. I used to routinely have directories with 500,000 files (very easy to reach such amounts with a cartesian multiplication of options). The result is simply downright appalling performance.

    • by tytso (63275) * on Saturday November 29, 2008 @05:28PM (#25927791) Homepage

      NFS semantics require that the data be stably written on disk before it can be client's RPC request can be acknowledged. This can cause some very nasty performance problems. One of the things that can help is to use a second hard drive to store an external journal. Since the journal is only written during normal operation (you need it when you recover after an system crash), and the writes are contiguous on disk, this eliminates nearly all of the seek delays associated with the journal. If you use data journalling, so that data blocks are written to the journal, the fact that no writes are required means that the data can be written onto stable storage very quickly, and thus will accelerate your NFS clients. If you want things to go _really_ fast, use a battery-backed NVRAM for your external journal device.

      • by whoever57 (658626)

        NFS semantics require that the data be stably written on disk before it can be client's RPC request can be acknowledged.

        Isn't that what the "async" option (to exportfs) is for? To allow the server to respond to the client before the write is complete?

        • Re: (Score:2, Interesting)

          by Anonymous Coward

          Sure. If you're a fan of catastrophic data loss, turn on async.

          The best NFS (v3) client mount options for a linux server with linux clients vary heavily with what you're actually doing and what you have, but the following is a good start:

          sync,hard,intr,nfsvers=3,rsize=32768,wsize=32768,
          acregmin=0,acregmax=0, acdirmin=0,acdirmax=10

          sync: don't use async! Ever!
          hard: better than soft!
          intr: allow interruptions despite hard! handy for failure situations!
          nfsvers=3: force nfsv3. You DO NOT want to use nfsv2!
          rsize

      • Re: (Score:3, Interesting)

        by pedantic bore (740196)

        NFS semantics require that the data be stably written on disk before it can be client's RPC request can be acknowledged.

        This hasn't been true since NFSv2. We're at NFSv4 now...

    • Re: (Score:3, Interesting)

      The CFQ IO scheduler has been able to link IO priority with process priority for ages. But there's a performance issue in the ext3 journaling code that has been affecting many people for some time....

  • It is rarely an issue to me, but once in a while it is convenient to be able to plug an USB disk on a machine with Windows or Mac OS X. What portable file systems are there that will cover those cases? Last I did some looks around a few years back I ended up concluding that the best option for a file system supported on both Linux and Windows was ext2 (with third party drivers for Windows). The only other file system supported on both was FAT, which have several drawbacks.

    Moving forward, what file system
    • Or how 'bout this, why isn't the underlying FS abstracted away from the OS? It seems that if you wanted to get out of the gooey compatibility mess, some sort of common interface would exist independent of OS calls to the hardware.

    • by jonbryce (703250)

      HFS+ seems to be the best option. You can get MacDrive for Windows (not free) which provides reasonably decent performance.

      Alternatively, there's NTFS. Only problem is that the NTFS3G drivers for Mac have extremely lousy performance. If you use the "stable" drivers, the time to fill a 250GB USB drive is measured in weeks.

    • by Knuckles (8964)

      ntfs comes to mind. It seems well-enough supported in linux distros for data disks you move around.

    • Re: (Score:3, Informative)

      by Ant P. (974313)

      Unless you're dealing with backward firmware/BIOS code that only understands FAT, you should be using UDF. Vista supports it, OS X supports it, Linux supports it, and everything back to win98 has readonly support - but you can get third-party drivers just like for ext2.

  • by r00t (33219) on Saturday November 29, 2008 @05:27PM (#25927779) Journal

    We're checksumming free disk space. That's dumb.
    It makes RAID rebuilds needlessly slow.

    We're unable to adjust redundancy according to
    the value that we place on our data. Everything
    from the root directory to the access time stamps
    gets the same level of redundancy.

    The on-disk structure of RAID (the lack of it!)
    prevents reasonable recovery. We can handle a
    disk that disappears, but not one that gets
    some blocks corrupted. We can't even detect it
    in normal use; that requires reading all disks.
    We have extremely limited transactional ability.
    All we get for transactions is a write barrier.
    There is no way to map from RAID troubles (not
    that we'd detect them) to higher-level structures.

    With an integrated system, we could do so much
    better. Sadly, it's blocked by an odd sort of
    kernel politics. Radical change is hard. Giving
    of the simplicity of a layered approach is hard,
    even when obviously inferior. There is this idea
    that every new kernel component has to fit into
    the existing mold, even if the mold is defective.

    • Re: (Score:3, Insightful)

      by tytso (63275) *

      Linux developers are aware of this issue; this is one of the things which is addressed by btrfs.

    • by Blackknight (25168) on Saturday November 29, 2008 @06:20PM (#25928109) Homepage

      What is this we? ZFS is the fix for all of the issues you mentioned, it does checksums on every block it writes and the RAID 5 write hole is history. You can also set how many copies per file you want to keep.

    • by Piranhaa (672441) on Saturday November 29, 2008 @06:29PM (#25928153)

      That's the goal of ZFS. Each block is checked with a 256-bit CRC checksum on every access. It incorporates a volume and partition manager in '1 tool', and knows where data is written to. On rebuilds it only repairs data that is actually there, which saves significant time. You should also setup weekly or bi-weekly scrubs (once a month for enterprise grade drives), which reads EVERY block written to and verifies it. This ensures that each block is still good, none is suffering from flipped bits, and that your disk isn't slowly failing on you.

    • Sure you can handle a few corrupt blocks on disk. RAID is built on the assumption that any hard disk has checksumming built right in. Without that RAID 5 would be impossible.
    • by dbIII (701233)

      We're unable to adjust redundancy according to the value that we place on our data.

      /usr /home /opt or home grown names like /data01 /data02 .... mount as required on whatever is appropriate.

      If you have more stuff than can fit on one volume you just mount the stuff you want treated in a paticular way on a paticular volume. As for access time, there is the atime option for that as with many other bits. By default things may not be well organised but it doesn't have to stay that way. As for the cry of "ker

  • worth a mention for large media space.

    http://www.dragonflybsd.org/hammer/index.shtml [dragonflybsd.org]

  • But... (Score:2, Funny)

    by El_Muerte_TDS (592157)

    is it ready for the desktop?

  • by Minigun_Fiend (909620) on Saturday November 29, 2008 @05:36PM (#25927849) Homepage
    ..called TLDRFS It simply ignores any files larger than 64KB.
    • Re: (Score:3, Funny)

      by Atriqus (826899)
      No, the cutoff should be 640K since 64K might not be enough for everybody.
  • by Britz (170620) on Saturday November 29, 2008 @06:02PM (#25928007) Homepage

    Maybe not for a desktop machine, but for servers I like to use XFS. That started way back then when XFS was the first (and then only AFAIR) fs that supported running on softraid. It was not that long ago and CPU cycles were already so cheap on x86 that softaid was already a pretty nice solution for small servers.

    For small servers I have not changed that setup (XFS on softraid level one on two cheap drives) ever since.

    I guess for the big machines it might be very different. I am pretty happy with XFS as it is.

  • I don't really care about better filesystems. ext3, NTFS and Mac OS Extended seem to be extremely reliable and work perfectly well on their respective platform.

    The only real problem I have is there doesn't exist a modern journaling FS which would work just as well on all 3 platforms.

    I can use ext3, but cannot plug it into a Mac.

    I can use Mac's FS, but cannot plug it into Windows (unless I pay for a proprietary driver every time I use that disk on a different machine)

    I can use NTFS, but cannot write to it on

    • Exactly. I can use ext3 in Windows, but only if I mount ext3 with the right options. For instance, when I installed openSUSE 11 on my dual-boot box, I decided to use writeback for journaling, and now none of the ext3 options for Windows can mount that drive. ntfs in Linux is painfully slow, even with ntfs-3g.

      I'm looking to build my next box with 4 x 1.5TB drives and I'm debating how to partition and format it for a dual-boot Windows/Linux setup. Do I keep most of shared media (I'm going to rip my entire

      • by ultranova (717540)

        For instance, when I installed openSUSE 11 on my dual-boot box, I decided to use writeback for journaling, and now none of the ext3 options for Windows can mount that drive.

        Ext3 is actually ext2 with a special file used for journaling. In fact you can create this journal on existing ext2 partitions to "convert" them to ext3. Assuming that the machine was shut down correctly, and all the data in the journal has thus been flushed to the disk, ext2 tools should mount it just fine as an ext2 volume - and if th

    • Re: (Score:3, Informative)

      by TrekkieGod (627867)

      The only real problem I have is there doesn't exist a modern journaling FS which would work just as well on all 3 platforms.

      I agree with you that's really important. I'd also like zfs to be that filesystem. However, as long as you don't need that drive to be the root drive of your respective file system, you might be interested in some of these links:

      I can use ext3, but cannot plug it into a Mac.

      Give this [sourceforge.net] a try. The latest news is that you get write support in Tiger, but I use it in Leopard without problems.

      Also don't worry about the ext2 part. Ext3 is designed to be backwards compatible with ext2. It can be mounted as ext2 (it just won't get journaling)

      You didn't ask

  • Reiser4 (Score:5, Interesting)

    by Enderandrew (866215) <enderandrew@g m a il.com> on Saturday November 29, 2008 @06:28PM (#25928149) Homepage Journal

    Hans was a jerk who has difficult to work with, and now he is a convicted murderer. That doesn't change the fact that Reiser4 as is may be the best desktop file system for Linux users, even with plenty of room for improvement.

    There are filesystems in development like Btrfs and Tux3 that look promising, but why should Reiser4 be abandoned? It is GPL. Anyone can pick it up and maintain it, or fork it.

    Does anyone know anything about the future of Reiser4?

    • Re:Reiser4 (Score:5, Interesting)

      by Ant P. (974313) on Saturday November 29, 2008 @06:55PM (#25928281) Homepage

      Reiser4 is still being maintained, by one ex-Namesys person IIRC.
      The main problem is the Linux kernel devs - they were too busy trying to find reasons to keep it out of the kernel (I can agree with their complaints about code formatting, but after that they descend deep into BS-land) to actually improve it. From the outside it sounds a lot like the story about the RSDL scheduler - completely snubbed because it stepped on the toes of one kernel dev and his pet project.

      • by acb (2797) on Saturday November 29, 2008 @08:56PM (#25928955) Homepage

        Over and above this, it'll need a new name. I know it doesn't make one iota technical difference, but people are fussy about such things; change the name, and people don't care if it was developed by fiends. Keep it and people will find excuses to edge away and it'll wither on the vine.

        The Volkswagen was a runaway success despite its Nazi origins, but had it been named the "Hitlerwagen", things would have probably turned out a lot differently.

        • I suggest doing everything possible to make reiser4 really really fast and have lots of bells and whistles. Then we should rename it to RicerFS.

      • Re: (Score:3, Informative)

        by StormReaver (59959)

        "From the outside it sounds a lot like the story about the RSDL scheduler - completely snubbed because it stepped on the toes of one kernel dev and his pet project."

        ReiserFS v4 wasn't included in the mainline kernel because Hans was being an even greater prick than usual to the kernel maintainers who asked him to fix his bugs and adhere to kernel coding conventions.

        RSDL wasn't included in the mainline kernel because Linus considered Con to be unreliable, and wanted to have a scheduler with a developer he co

      • by dbIII (701233)
        To putt words in the mouth: the "it is perfect even though it is not finished and you will bow to my authority and change the kernel to make it fit" attitude when the reality was at the time a buggy and unrecoverable from corruption filesystem was what kept it out of the kernel. When you start off like that it's pretty hard to work together. Personally I don't think it's done yet since there is not much you can do to get things back with even minor filesystem corruption - so if I was responisible I would
    • They need to give Hans an Internet connection in his cell. At least then he can still be of some use to society, and it's not as if his was a computer-related offense...

    • What you meant to say was "Hans had inter-personal social issues which evolved into violent inter-personal social issues."

      That said, I've often found anti-social people can make excellent programmers.

      Now go away! :-)

  • by millosh (890186)
    Whenever I have to install some server, I have a metaphysical question: ext3 or reiserfs?

    Ext3 has a lot of advantages, including a possibility to do a fast recovery of files. While it is not needed often, at least once per year I have such demand. At the other side, undelete methods with raiserfs are very problematic.

    At the other side, my servers are up usually for a year or more. This means that the most of company's employees may go on one day vacation whenever I want to reboot a machine with 4TB file sys
    • by LWATCDR (28044)

      JFS?

    • by tytso (63275) *

      The ext2/ext3/ext4 filesystems do a periodic check of the filesystem for correctness out of paranoia; because PC class disks, well, have the reliability of PC class disks, and that's what most people use these days on Linux systems. Other filesystems, such as reiserfs and xfs, are subject to the same kind of potential random filesystem corruption caused by hardware errors that ext3 is; in fact, in some cases their filesystem formats are more brittle than ext2/3/4 against random hardware failures in that a

  • JFS (Score:5, Insightful)

    by adrianbaugh (696007) on Saturday November 29, 2008 @08:49PM (#25928915) Homepage Journal

    Sad to see JFS being overlooked so. While it may not have the postmodern features to compete in the wake of JFS, it's still in many cases the best current filesystem for linux. It's remarkably crashproof, has the lowest CPU loading of any of {ext3 jfs xfs reiser3}, good all-round performance (generally either first or second in benchmarks) and is fast at deleting big files. I haven't used anything else in a couple of years - I used to put reiser3 on /var, but got fed up with its crash intolerance. It's sad to see jfs so overlooked, because at least until btrfs or tux3 come out it's arguably the best option available.

  • by Anonymous Coward
    seriously how many filesystems do we need? this is the failing of OSS, too many projects inventing the same thing splitting up their developing efforts so neither of them achieve anything.

You see but you do not observe. Sir Arthur Conan Doyle, in "The Memoirs of Sherlock Holmes"

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