On Monday, April 30, 2012 10:53:46, Camaleón wrote: > On Sun, 29 Apr 2012 20:16:58 +0200, Martin Steigerwald wrote: > > Am Dienstag, 24. April 2012 schrieb Camaleón: ... > > XFS might also have long file check times. > > I still have not tried this so I can't really tell but what I've heard on > XFS is not comparable to ext3, I mean, in regards with the time it takes > to perform a filesystem check. On XFS, fsck is literally a no-op -- it does *not* fsck the filesystem. The steps to actually fsck a XFS filesystem: - mount the XFS filesystem to replay the log - unmount the XFS filesystem that was just mounted - run xfs_check on the filesystem's device - if necessary run xfs_repair on the filesystem's device Note this means running 'xfs_check' is done when the filesystem is not mounted. _Supposedly_ it can also be run if the filesystem is mounted read- only, but in practice I find it's best (and easier) to run the XFS commands from a LiveCD. The xfs_check and xfs_repair operations are incredibly fast -- even for a 500GB filesystem it's usually only takes about 10 or 15 seconds. Speed is generally what XFS is good at, *except* when it comes to deletion of a large number of files -- that's where it's slow. Also in practice I find that any kernel crash or hard-power-off corrupts XFS to at least some extent requiring an xfs_check and xfs_repair, so I have to make sure to keep a LiveCD on hand to be able to do this. This gets even more interesting when running XFS on top of LUKS encryption. I'm currently doing that, and I have had to do an xfs_repair operation -- it involves running cryptsetup manually at the command line within a LiveCD and then running xfs_repair on the newly created unencrypted device. [And of course you have to know to look and make sure the LiveCD contains those utilities.] Definitely an interesting experience. The main reason I've been running XFS is for speed -- even on top of LUKS I'm finding XFS is able to do sustained 40MB/s transfers over 1Gb ethernet, where ext4 on the same box is not able to sustain that. However ext4 is more reliable and easier to deal with, because it's able to run an fsck at boot time and without neeting a LiveCD to fix it. ;-) -- Chris -- Chris Knadle Chris.Knadle@coredump.us GPG Key: 4096R/0x1E759A726A9FDD74
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