[HN Gopher] The SGI XFS Filesystem
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The SGI XFS Filesystem
Author : ecliptik
Score : 26 points
Date : 2023-05-12 20:21 UTC (2 hours ago)
(HTM) web link (blog.koehntopp.info)
(TXT) w3m dump (blog.koehntopp.info)
| wazoox wrote:
| XFS is incredibly robust. I manage many petabytes of XFS
| machines. Some have XFS volumes in the 2 PiB range. And it's also
| extremely fast. And I remember when I created my first folder
| with several billion files and it just worked :)
| MichaelZuo wrote:
| How does it compare to ReFS or other more recent systems?, if
| you've ever looked into it.
| jeffbee wrote:
| One thing I have long been suspicious of, but never swept out the
| parameter space to know for sure, is how one should set sunit,
| swidth, agcount or agsize to exploit the parallelism of an SSD
| and modern CPU. Used to be that sunit, swidth, and agsize were
| critical for RAIDs because getting them wrong would mean weird
| stripe misalignment, and if you did not set agsize all of your
| metadata load would be on a subset of the array. These days an
| SSD has way more natural parallelism than any RAID ever had, and
| we have more CPU cores than ever. Are we supposed to be setting
| sunit, swidth, and agsize? Or does the flash translation mean it
| doesn't matter? And how best to mkfs.xfs when your SSD offers LBA
| sizes other than 512?
| miohtama wrote:
| Does XFS offer benefits or tradeoffs of ZFS/ext4/others today?
|
| I have been using it with Linux since early 2000. But I am not
| sure how the file-system development has been lately e.g. with
| the SSD revolution.
| DiabloD3 wrote:
| I think you meant ZFS, not zsh.
|
| I use both XFS and ZFS. XFS in any situation where it is a
| single drive (ie, my laptop), ZFS in any situation where I'm
| doing actual fault tolerant high performance storage stuff.
|
| I don't see where ext family really matters in modern storage.
| If I decide to not use XFS anymore, there are flash-dedicated
| filesystems that will beat ext in performance and reliability
| on SSDs that better fit the future.
| miohtama wrote:
| Fixed, thank you!
| XorNot wrote:
| ZFS is actually ideal for single drives because even if you
| can't do recovery, knowing a file has corrupted is extremely
| valuable.
| theodric wrote:
| I'm too lazy to summarize this beyond saying both ext4 and XFS
| have their advantages and disadvantages, and both are still
| under active development. ZFS is a funny and problematic one
| that does lots of cool tricks but isn't properly free and
| gobbles resources.
|
| Check this: https://linuxhint.com/xfs-vs-ext4-brief-comparison/
| arp242 wrote:
| ZFS (or rather, OpenZFS) is absolutely Free Software and Open
| Source under any definition. Richard Stallman will tell you
| the same thing.
|
| It just has an unfortunate license that's not GPL-compatible
| and this causes problems with GPL kernels (e.g. Linux), which
| is a _very_ different thing than "not being properly free".
| yjftsjthsd-h wrote:
| ZFS is absolutely Free Software, it's just that its license
| isn't GPLv2 compatible. (Bearing in mind that by the same
| stroke, GPLv3 isn't GPLv2 compatible.)
| chasil wrote:
| If you look at database benchmarks on TPC.org, you will find
| that many of them are on XFS (as a consequence of using
| RHEL/CentOS), which was designed with database performance in
| mind.
|
| It used to be necessary for Oracle to use raw partitions to get
| the very best database performance. I haven't heard of anyone
| doing that for many years.
|
| "The default implementation in most kernels is simply a file-
| global lock placed at the in-memory inode, making sure there
| can be only one writer per inode. Implementers of databases
| hate that because it limits the write concurrency on any single
| file to One. This is, for example, why Oracle recommends that
| you make tablespaces from multiple files, each no larger than
| one GB.
|
| "XFS, in O_DIRECT mode, removes this lock and allows atomic,
| concurrent writes, making database people very happy."
|
| Developers at Oracle have posted a number of blog posts on
| their code changes for Linux XFS.
|
| https://blogs.oracle.com/linux/post/introduction-to-xfs-tran...
|
| https://blogs.oracle.com/linux/post/xfs-online-filesystem-ch...
|
| https://blogs.oracle.com/linux/post/xfs-2019-development-ret...
|
| https://blogs.oracle.com/linux/post/xfs-whats-new-and-whats-...
|
| There can be a strong bias against Oracle at HN (and I
| understand why) but credit must be given where it's due.
| miohtama wrote:
| ZFS is also from Oracle, right? Seems like a dominating force
| in the FS industry if one can call it a such.
| chasil wrote:
| Btrfs is the filesystem for which they are most
| responsible.
|
| They explicitly do not support its use for their database.
|
| "[Btrfs] was initially designed at Oracle Corporation in
| 2007 for use in Linux, and since November 2013, the file
| system's on-disk format has been declared stable in the
| Linux kernel."
|
| https://en.m.wikipedia.org/wiki/Btrfs
|
| They own the rights to ZFS by way of their purchase of Sun
| Microsystems.
|
| Oracle is a power player in the realm of Linux filesystems,
| no doubt.
| arp242 wrote:
| Linux uses OpenZFS, which is a fork of OpenSolaris' ZFS;
| they haven't shared any code since 2010 AFAIK.
| ilc wrote:
| ZFS is Sun.
|
| BTTFS is Oracle.
|
| And neither have anything to do with a database, IMHO.
| whiskeytuesday wrote:
| I mean, in that it came out of Sun, kind of I guess.
| DiabloD3 wrote:
| I'm a fan of XFS. I've used it for over a decade for all systems
| that don't need ZFS.
|
| In fact, due to the lifespan of the headless box under my desk
| (ie, predates bootable ZFS root partitions under Linux), its root
| partition is still XFS, while the actual real storage is ZFS
| managed
| liendolucas wrote:
| I think the main issue with ZFS is that you need to learn a lot
| of concepts to actually understand how to do things correctly
| and don't fuck up.
|
| To this day I've written some personal notes as warning
| reminders to be careful about certain operations. I can't
| remember the exact terminology (I believe these are called
| "attributes" or "features" in ZFS), but what happened to me not
| long ago was that if I created a ZFS filesystem (along with a
| pool) from Ubuntu it was creating some of these features that
| ZFS on FreeBSD didn't properly recognize and didn't allowed me
| to successfully mount it.
|
| The other way round creating it from FreeBSD and then mounting
| it on Ubuntu worked as expected. The thing with these
| "features" is that they can be "promoted" or "upgraded" and in
| this case if you do so will again render the ZFS unavailable to
| be mounted in FreeBSD. I spent a whole day on this until for
| some reason I decided to print this list and effectively
| compare and do some online search about it.
| mustache_kimono wrote:
| > if I created a ZFS filesystem (along with a pool) from
| Ubuntu it was creating some of these features that ZFS on
| FreeBSD didn't properly recognize and didn't allowed me to
| successfully mount it.
|
| I mean... _shrugs_ ...you could format it as XFS and not be
| able to mount on FreeBSD either? Seems like feature flags is
| a good way to solve this problem.
| liendolucas wrote:
| I was actually going to ask that... Is XFS a good
| "portable" filesystem across GNU/Linux and different BSD
| flavors? Native support or through FUSE? The use case are
| USB drives. I don't mind losing visibility on Windows or
| MacOS, just to work flawlessly between these without major
| efforts.
|
| Edit: Added some comments.
| mustache_kimono wrote:
| ZFS is really one of the only games in town AFAIK for
| serious filesystems. UFS might also work? Of course there
| is always exFAT, etc.
| liendolucas wrote:
| I could be wrong but I didn't go with UFS because
| apparently there are significant implementation
| differences among BSDs. I was kind of surprised to
| discover that.
| bombcar wrote:
| XFS was the first time I felt i had a "real" file system on
| Linux, ext2 being long in the fsck and reiserfs doing strange
| things with tail packing.
| blipvert wrote:
| 25+ years using XFS (IRIX user). Never a single problem
| (hardware failures aside).
|
| My go-to filesystem.
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