On Thu, Jan 27, 2011 at 3:44 AM, Bergmann, Chr. Carl <chbe AT risoe.dtu DOT dk> 
wrote:
> I have some problem with poor performance when I backup Windows 2008 R2 ISCSI 
> filesystems.
>
> When I backup the C:\ (local disk on server) I see 50-75Mb/sec.
>
> When I backup E:\ (ISCSI EMC SAN partition) I see 500-1000Kb/sec
>
> Anyone have an idea how to speed up ISCSI?
>
> When I backup ISCSI partition on an older win2008 (not R2) I get very god 
> performance.


This sounds very much like a non-backup specific issue.  In your
position, do you have any insight into the performance of the
underlying disk?  Perhaps they are starved for iops.  Is the
array-side performance otherwise identical during the times these 2008
and 2008 R2 machines are backed up?

Is the networking configuration identical between the 2008 and 2008R2
hosts?  Is the network fully optimized, such non-blocking switches
using jumbo frames? and is it a dedicated network?

Is multipath correctly configured for the EMC device, and you are not
"trespassing" or otherwise using an unoptimized path?

Are there any major differences between the file systems of the 2008
vs the 2008R2 hosts, such as the number of files and their average
size?  Larger numbers of smaller files may back up slower than the
opposite.  Any differences in alignment or disk labels, partition
offsets that would introduce inefficiencies on the storage device?

Good luck,
Eugene

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