performance degradation backing up small files
 

Has anyone experienced performance degradation when backing up large
volumes of files from a NAS array? I am researching complaints that
backing up large volumes of small files (128k)results in a noticeable
performance drop. One suggested solution was to segregate small files
and back them up over the LAN rather than the SAN. Does this make
sense?

Thanks,
Alan

"alan" wrote in message
m...
Has anyone experienced performance degradation when backing up large
volumes of files from a NAS array? I am researching complaints that
backing up large volumes of small files (128k)results in a noticeable
performance drop. One suggested solution was to segregate small files
and back them up over the LAN rather than the SAN. Does this make
sense?

Thanks,
Alan

First step is to find out where the bottleneck is. With large numbers of
small files, maybe the disks are overwhelmed by seek requests. More often
the backup software has a bottleneck keeping track of all those small
transactions in the index database.

Measure disk I/O on the NAS, and on the backup server. Find out where the
bottleneck is. Once you find that out, it's time to talk about possible
fixes.

Rob

In article ,
alan wrote:
Has anyone experienced performance degradation when backing up large
volumes of files from a NAS array? I am researching complaints that
backing up large volumes of small files (128k)results in a noticeable
performance drop. One suggested solution was to segregate small files
and back them up over the LAN rather than the SAN. Does this make
sense?

Thanks,
Alan


Is this thru an ethernet switch ? FWIW I once saw a _very_ strange
problem that sort of fit your description. After eliminating lots of
things, I sort of narrowed it down to the switch (an otherwise
excellent HP procurve box in use for a year.) A call to HP support
told me quickly that it was a "known problem" and that I should reboot
the swicth. If the problem reoccured there was a microcode update
avaiable.

FWIW

--
Al Dykes
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adykes at p a n i x . c o m