RE: Question on gathering System Statistics
Date: Fri, 29 Jan 2021 02:43:20 +0000
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Thanks Jonathan.
Thank you,
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A key question to ask first is whether you had system stats set/collected on the vmax250 and whether this was done in combination with setting the db_file_multiblock read count or leaving it to default, and had you done anything with the calibrate_io option?
Ideally you probably want to believe that if you get the same plans with the Powermax you'll get the same, or better, performance. But if you do something that changes the optimizer's arithmetic you may get plan changes that result in random variations in performance.
If you don't know what you've done about system stats in the past there's a script at the end of this blog note that will report them for you:
https://jonathanlewis.wordpress.com/2019/08/14/gather_system_stats/
Regards
On Tue, 26 Jan 2021 at 19:30, Hameed, Amir <Amir.Hameed_at_xerox.com<mailto:Amir.Hameed_at_xerox.com>> wrote:
Hi,
Thanks,
System statistics were collected in the past and also recently with the NOWROKLOAD option, which is what Oracle suggests for Oracle E-Business Suite R12 databases. The MRBC value was not set. What I find interesting is that the IO statistics numbers on both storage frames (VMAX250F versus PowerMax) are identical. I would also like to understand what the value of IOSEEKTIM represents in the world of SSDs or All Flash Array storage.
SaveTime Stat Name Value
------------------------- --------------- ------------------------------
26-JAN-2021 23:07:15 CPUSPEED
26-JAN-2021 23:07:15 CPUSPEEDNW 3,528
26-JAN-2021 23:07:15 IOSEEKTIM 10
26-JAN-2021 23:07:15 IOTFRSPEED 4,096
26-JAN-2021 23:07:15 MAXTHR
26-JAN-2021 23:07:15 MBRC
26-JAN-2021 23:07:15 MREADTIM
26-JAN-2021 23:07:15 SLAVETHR
26-JAN-2021 23:07:15 SREADTIM
Current CPUSPEED
Current CPUSPEEDNW 3,518
Current IOSEEKTIM 10
Current IOTFRSPEED 4,096
Current MAXTHR
Current MBRC
Current MREADTIM
Current SLAVETHR
Current SREADTIM
Amir
Subject: Re: Question on gathering System Statistics
Jonathan Lewis
We are in the process of moving our applications from current storage array (VMAX250) to a new array (Powermax). From best practices standpoint, should we collect System Stats after moving to the new storage? If we should then is there a recommended way of gathering System Stats?
Amir
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Received on Fri Jan 29 2021 - 03:43:20 CET