Dexter Filmore wrote:
http://gentoo-wiki.com/HOWTO_Gentoo_Install_on_Software_RAID#Data_Scrubbing
"Warning: Be aware that the combination of RAID5 and loop-devices will most
likely cause severe filesystem damage, especially when using ext3 and
ReiserFS. Some users suggest that XFS is not affected by this, but this has
not been entirely confirmed. See kernel bug 6242 for updates on this bug.
Note: There are also reports that Journaled Filesystems are problematic on all
Software-RAID levels. No kernel bugs have been submitted regarding this bug
as of yet. A number of the reports involve using cryptoloops which are known
to cause corruption. See http://forums.gentoo.org/viewtopic-t-412467.html for
more information. This thread should be taken with a grain of salt."
Can someone shed some light on this? I have XFS on my raid and *had* problems
when unpacking large archives with many small files.
To start, the report mentions a number of unrelated layers, evms,
dm-crypt, and some total misinformation, claiming that evms is needed to
allow growing of raid. I can't speak to XFS over RAID, I've seen report
of XFS problems on native partitions, and just don't have enough
information to have a good opinion.
But I have been running ext3 over RAID1 and RAID5 for years, and just
haven't seen the problems you mention, or anything else which concerns
me. There were recovery issues in early kernels, but I have no reason to
think that there's any basic problem at this point. Reports of problems
often outlive the problem, and problems with multiple layers of device
manipulation you increase the chance of failure, because a chain is as
strong as the weakest link, and decrease the chances if identifying
which layer is actually a problem. If you have any hardware issues, you
now depend on every layer not only handling them, but passing them up
and down layers.
I have put lvm over raid, but even that would be an issue to debug. I
would simplify if I had your problem.
--
bill davidsen <davidsen@xxxxxxx>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979
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