Recommended stripe size on VxVM volumes

[Sanjay Kumar Suri]

I have following doubts:

1. What is the ideal recommended stripe size on VxVM volumes?

2. Is the stripe size has any bearing on the Oracle database performance?

Let me know any resource to get more info on this.

Thanks.

sks

[G. Vrijhoeven]

Hi,

I would say the ideal stripe size depends on the system. If your system is used as a news server ( large number of small files) it is different than a database ( few large files ).

For a oracle database i would have a talk with the DBA. His SGA block size (e.g. 8k )could be the ideal striping size.

Gideon

[Stefan Farrelly]

generally speaking 64k is the optimum. We use it for all our oracle databases. ocasionally a larger stripe may be even more beneficial.

[Ralph Haefner]

It depends on the storage hardware and the workload. At my last job we had large Oracle databases used for data warehousing. We brought in new storage, and before setting up our servers we did lots of testing by creating identical volumes except for one parameter and running a battery of I/O tests. We found that using a StorageTek D280 SAN array using 128K was best, with 256K being a close 2nd. When we had EMC storage before that we also used 128K, but in that case it was just a guess without much testing to show if that was best.

I think that with Oracle databases like ours (data warehousing, not OLTP) the larger you make the stripe the better since your typical writes and reads are much larger than the stripe size anyway.

Of course, if your workload or hardware is different, the only way to be sure the suggestions above are right for you is to do some testing...

[Sanjay Kumar Suri]

Dear all

Thanks for the insight. To give an idea about our system.

We are using Superdome with 8 CPU and 16 GB RAM. Oracle data (8.1.7) is stored on XP512. Database size is 1 TB. DB growth is 30 GB per month.

We are running SAP 4.0 B with 1200 concurrent users at peak time. It is an OLTP system but lot of READ only kind of activity.

Will this info helps to answer my question?

Regards.

sks

[Steven E. Protter]

As Stefan points, out Oracle seems to like those big stripes, 64 Kb.

Do note that Oracle actually recommends raid 1 or raid 10 for data, index and redo logs, not striping.

They have gotten flexible about this, but raid 1 or 10 is faster.

Sources ....

technet.oracle.com

SEP

[Ralph Haefner]

I've never used that exact hardware before, but my guess is that with the setup you said my suggestion of 128K or 256K stripe sizes is probably too big. Our databases were around a terabyte like yours, but 20 users was a busy day. We had much fewer but larger transactions than your OLTP system would have.

If you have to guess without testing, I'd probably go with 64k like the other posters have said. If you do have time to test, try a benchmark run with 64k, then test both 32 and 128 to make sure neither performs better. If either is an improvement continue moving the same direction with either 16 or 256 as appropriate.