Greetings,
There are of course many things that can affect throughput. CPU and RAM are two of those of course. Another is the number of disk arms and paths to those arms. If the system has insufficient resources to get data from disk it will consequently back up more slowly. So that's 1.
Then there is the data being backed up. For IBM i for example it will typically stream very large objects more quickly than a large number of small objects. If the partitions have the same mix of data and disk arms then they would be expected to perform similarly.
Another is the path from the server to the VTL. If it is the identical same path as the faster partition then likely that isn't it. Note that with VIOS in play this is very possible. Both partitions could be mapped to the same physical port and thus take the same path to the VTL. However if that path is different then it brings into play the fiber cables as well as settings on the switch ports. In this case check the switch settings carefully. We have noted:
a) ports set to a lower speed for some previous use.
b) ports showing vast numbers of errors
c) ports with failing SFPs (yes they do eventually wear out!)
Also verify that you don't have too many partitions sharing the same path such that a port is congested.
Hope some of this helps you track down your issue.
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Larry Bolhuis
Chief i-entist
Frankeni Technology Consulting, LLC
Middleville MI
6162604746
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Original Message:
Sent: Wed December 15, 2021 07:32 AM
From: Nahla Alloush
Subject: Transfer Rate for backup on VTL
Hello again,
I already raised the below issue before that time duration for a daily backup is taking the shortest time on Mondays and the longest time on Saturdays, and I am raising it again to ask about a certain point. Just noticed that the average transfer rate from PRTRPTBRM for this partition is around 30 GB/HR while the average transfer rate for the daily backup for another partition is around 300 GB/HR. The partition with the lower transfer rate has more CPU and more RAM. Both partitions are using the same VTL and backup is running in a non restricted state. Any idea what could be the reasons behind having that much difference in transfer rates ? Thanking you in advance.
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Nahla Alloush
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