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Don't forget the all-time classic false performance problem when comparing "old" to "new". Especially if the apparent problem is confined to a special something. Like a particular batch job. Sometimes what is happening is just that the new system has a cold cache. The numbers that you have from the old system are almost certainly with a hot cache. It seems silly but I've seen people ready to toss out some very expensive and quite capable hardware because they overlooked that. Of course it might be other issues (NUMA is a glaring possibility) but it never hurts to double check the obvious. On 12/9/14, 4:21 PM, TheMadDBA wrote: RE: Performace degradation between / /Power8 Reply by TheMadDBA It is very easy to get misleading results with ndisk (and other tools like that). For example: reading small files over and over again will most likely read from the AIX or SAN buffer cache instead of actually hitting the disk. This makes the hardware seem much faster than it really is. There aren't really any magic switches to flip between AIX7 and AIX8. A few things to check.... 0) Does your new LPAR span NUMA zones? This can be a huge problem. 1) Check your Progress startup parameters and DB settings to make sure they are the same. 2) Compare the output of the following commands on both AIX boxes.. looking for differences ioo -a (io related parameters) vmo -a (memory related parameters) lsps -a (paging space) 3) use nmon and iostat to compare what is going on with memory,cpu and disk during your tests (on both systems) 4) use promon to compare what is happening at a database level (on both systems) 5) check the queue_depth settings on all of your disks using lsattr -El hdiskname How big is your database and each AIX LPAR? Is this batch job a single Progress session or a collection of processes? Stop receiving emails on this subject. Flag this post as spam/abuse. -- Tom Bascom 603 396 4886 tom@greenfieldtech.com
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