[CentOS] 11TB ext4 filesystem - filesystem alternatives?

Fri Sep 28 20:29:55 UTC 2012
Keith Keller <kkeller at wombat.san-francisco.ca.us>

On 2012-09-28, Ilyas -- <umask00 at gmail.com> wrote:
> One day our servers farm rebooted unexpectedly (power fail happened)
> and on centos 6.3 with up2date kernel we lost few hundred files (which
> probably was opened for reading, NOT writing) on XFS.
> Unexpected power lost follow to situation when some files get a zero size.

No filesystem can fully protect against power failures--that's not its
job.  That's why higher-end RAID controllers have battery backups, and
why important servers should be on a UPS.  If you are really paranoid,
you can probably tweak the kernel (e.g., using sysctl) to flush disk
writes more frequently, but then you might drag down performance with

IOW, it's nice to have fsck, but it's better to take steps to avoid
needing it.

That being said, through a series of unfortunate events, I've lost power
on some of my larger XFS filesystems, and in those rare events I have not
seen or heard about any files lost.  So I strongly suspect other factors
in your data loss--if XFS was involved, there were probably also other
issues involved as well.


kkeller at wombat.san-francisco.ca.us