Re: Inconsistent Backup Performance
1996-08-19 17:03:18
On Mon, 19 Aug 1996 16:33:31 -0400 Jim Kleberg said:
> We are now testing ADSM UNIX backups using MVS as a server. Even
> though our testing environment is fairly well controlled, our data
> transfers (over TCP/IP) vary widely (.4 to 1 MB/sec) over a 10mb
> switched ethernet connection. This is within a minute or 2 of each
> test.
> Does anyone have any ideas as to what to look for?
Performance testing is a tricky business. If you are doing smallish tests,
then one thing you must beware of is AIX filesystem cacheing. The second
test may pull pages out of memory cache buffers instead of off of disk.
Network I/O may not be your bottleneck. Pulling the data off of disk is
more likely to be your bottleneck.
Paul Zarnowski Phone: 607/255-4757
Cornell Information Technologies Fax: 607/255-6523
Cornell University US Mail: 315 CCC, Ithaca, NY 14853-2601
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