Disk IO issues

James Antill james at fedoraproject.org
Thu Jan 1 06:47:45 UTC 2009


On Wed, 2008-12-31 at 14:42 -0600, Mike McGrath wrote:
> Lets pool some knowledge together because at this point, I'm missing
> something.
> 
> I've been doing all measurements with sar as bonnie, etc, causes builds to
> timeout.
> 
> Problem: We're seeing slower then normal disk IO.  At least I think we
> are.  This is a PERC5/E and MD1000 array.
> 
> When I try to do a normal copy "cp -adv /mnt/koji/packages /tmp/" I get
> around 4-6MBytes/s

 This _might_ not be "IO" in a normal sense, -a to cp means:

 file data + file inode + ACLs + selinux + xattrs [+ file capabilities]

...esp. given that you aren't getting large IOWait times, you might want
to strace -T the cp and do some perl/whatever on the result to see what
is eating up the time.
 This is a straight 5.2, yeh?

-- 
James Antill <james at fedoraproject.org>
Fedora




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