[CentOS] 32-bit kernel+XFS+16.xTB filesystem = potential disaster (was:Re: ZFS @ centOS)
Warren Young
warren at etr-usa.com
Wed Apr 6 20:08:52 UTC 2011
On 4/6/2011 1:16 PM, Lamar Owen wrote:
>
> There are other issues with XFS and 32-bit; see:
> http://bugs.centos.org/view.php?id=3364
> and
> http://www.mail-archive.com/scientific-linux-users@listserv.fnal.gov/msg05347.html
> and google for 'XFS 32-bit 4K stacks' for more of the gory details.
Thanks for the info.
The problem seems to be tied to LVM and high amounts of I/O,
particularly writes. None of that applies to this application. The
filesystem is a plain-old partition, the array is mostly going to be
read-only, and due to a bottleneck elsewhere in the system, the peak
read rate can't be higher than 20 Mbyte/s.
(If you're wondering, then, why I bothered to benchmark the system at
all, it's because we get much higher I/O rates when initially loading
the array up, so that the low write speed of ZFS-FUSE would have
increased that initial load from days to weeks.)
That load went off without a hitch, so we've probably already done the
worst thing to this server that it will ever see. (Kind of like the old
advice for happiness: eat a bug every morning, and nothing worse will
happen to you for the rest of the day.)
We'll test it under load before shipping it anyway, however.
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