Benchmarking Linux filesystems on software RAID 1 (Lone Wolves)

Posted Apr 22, 2008 12:18 UTC (Tue) by dgc (subscriber, #6611)
In reply to: Benchmarking Linux filesystems on software RAID 1 (Lone Wolves) by kev009
Parent article: Benchmarking Linux filesystems on software RAID 1 (Lone Wolves)

> He's worried about data loss from power failure but then chose
> to use XFS...

FWIW, I think your information is out of date.

We put fixes into 2.6.17 that worked around the problem
that caused "data loss on power fail" pretty effectively,
and we fixed it properly in 2.6.22. I haven't seen a bug report
for "NULL files" on power loss or crash since 2.6.17....

If it's still happening to you on a recent kernel then please
report it. Otherwise, you need to find some other reason not
to use XFS. ;)

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Benchmarking Linux filesystems on software RAID 1 (Lone Wolves)

Posted Apr 22, 2008 16:15 UTC (Tue) by bronson (subscriber, #4806) [Link] (2 responses)

Wow, this is big news!  I'm surprised I never heard this.

I suggest you put it at the very top of your readme or something: XFS NO LONGER CAUSES DATA
LOSS ON POWER FAIL.  REPEAT.  XFS NO LONGER CAUSES DATA LOSS ON POWER FAIL.  Because pretty
much everyone I know is still laboring under this misconception!

Benchmarking Linux filesystems on software RAID 1 (Lone Wolves)

Posted Apr 23, 2008 16:46 UTC (Wed) by alankila (guest, #47141) [Link] (1 responses)

I'm thoroughly ignorant on this issue. I thought that basically all journalling filesystems
guarantee only that there is consistency of filesystem after service interruptions.

Was the nature of XFS's empty files problem somehow more severe than you'd expect to get in
other filesystems? I mean, data only in system RAM is lost no matter what. But once it's
partially or fully in journal, it should have been preserved. Did XFS not recover file data
for situations where it could have done so?

Benchmarking Linux filesystems on software RAID 1 (Lone Wolves)

Posted May 3, 2008 18:42 UTC (Sat) by anton (subscriber, #25547) [Link]

The way I have heard it, XFS used to zero files that were partially written. I have been bitten by such behaviour, although with a different file system. In my case I lost an hour of work.