Differences in cpu utilization between rx4660 and N-Class

[Tim D Fulford]

Hi

> They are using the same physical RAID
> storage device (EMC CX600) using RAID5 but
> the NClass has its database spread over
> more RAID (7 RAID of 5 disks each) as
> opposed to the rx4640 (4 RAID of 5 disks
> each). So basically, smaller luns on more
> spindles vs bigger luns on less spindles.

So If I'm reading this right then you are using 35 disks on N-Class & 20 on rx4640; If the N-class is falttening its disks, then the rx4640 will only do about 1/2 of the IO before it flattens its disks... If you are able to get the rx4640 box another 3 LUNs (not quite doubling its IO capacity) you should be able to get it to go at a similar speed as the N-Class.

You might want to re-assure yourself by looking at the IO stats also..

can you post "typical" sar -d on the two systems?

Regards

Tim

[Jean-Luc Oudart]

Hi,

there is may be another possibility.
There is a bug 3048318 where some DBMS_STATS gather options can be slow. It's been confirmed for 9.2.0.4 and affect "most" platforms.
The fix is to install 9.2.0.5 patch set.

source Metalink

Regards
Jean-Luc

[J.D._3]

Hi Tim,

We'll be trying out another test where we would actually be using the LUNS from the NClass and move them all into the rx4640 and testing it that way. We're thinking its a little bit closer to comparing the 2 different architecture. At least this way we can isolate the issue a bit more.

Jean-Luc,
My apologies for mentioning that the databases are 9.2.0.4. They're actually 9.2.0.6. We've been running 9204 a while and I got so used to typing that instead of the actual version we're running now.

We're hoping to do this test this week. I'll keep everyone posted. Thanks again for the replies.