ADSM-L

Re: [ADSM-L] Tsm server possibly limiting backup performance

2011-05-27 11:16:30
Subject: Re: [ADSM-L] Tsm server possibly limiting backup performance
From: Richard Sims <rbs AT BU DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Fri, 27 May 2011 10:49:40 -0400
The networking itself is just one element in the overall backup operation...  
You don't say what measurement point you are looking at for your throughput 
numbers.  If it is the "Network data transfer rate" TSM summary statistic, that 
reflects TSM interacting with the network layer of the operating system, with 
affecters such as TSM TCPWindowsize, Path MTU Discovery where that is in 
effect, etc.  Unexpected, elongated network routing can delay things; but your 
FTP test should have run into that if were a factor...unless conditions are 
changing depending upon time of day.  When a TDP is involved, it can only pass 
data as fast as the back end application provides it.  A traditional B/A backup 
can be impaired by the paging incited by the amount of memory taken by the 
Active files list.  If standard measurement points don't reveal a cause, a 
client trace with a representative data set can be illuminating.

    Richard Sims