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networker 8.1 - parallel save streams (PSS) - a maximum of 4 streams per save set ???
Hi,
We are new to the recent feature of Networker (8.1) - parallel save streams (PSS).
We wanted to test this new tool under UNIX. I played around a bit to have an idea about the scalability of this: how the backup speed looks like with a single stream (stream#=1), then two, four etc streams per one single save set.
When trying to test PSS with eight (8) streams per one single save set, I realized that only four (4) streams are actually used. I double-checked in the docs ("Performance Optimization Planning Guide"?) and my understanding is that this (stream#=4) is an actual hard limit, by design:
"The number of streams for each PSS save point is determined before the backup from its
client parallelism value and it remains fixed throughout the backup. It is a value from 1
through 4 (maximum), ..."
I wonder whether there is a way to work this around, because the server and the disk config under the file system (save set) to be backed up - we believe - can manage many more parallel streams: another legacy backup utility actually compresses the Oracle data files (hundreds of those) on this file system at the very same time. The file system is set to CIO concurrent I/O under AIX, and its I/O scales very well with multiple streams. It also has a large number of disk drives (spindles) underneath, from a quick EMC VNX storage array.
So PSS with 8 or 16 streams could be a benefit for us.
Any experience, idea, or workaround for this?
Thanks.
Regards,
Geza