RE: To use SAME or NOT for High End Storage Setup ? .... Stripe Unit Size 32 MB Vs. 64 KB ?

Hi,

My experience, for what it's worth, has been to use 4 MB stripe size using the volume manager. I've done this on HP-UX with both an IBM Shark arrary and an EMC Symmetrix array. In both cases performance was fine and there were no "hot"
disks. The logic for choosing 4 MB was to ensure that any full table scans (in our case 128 KB) would avoid having the multi-block reads split into two reads due to the required blocks existing in more than 1 "stripe".

We didn't get the chance to test using different stripe sizes.

IMHO I'm not sure why IBM are recommending why you should go as large as 32 MB.

Cheers,

Chris

Quoting VIVEK_SHARMA <VIVEK_SHARMA_at_infosys.com>:

> Folks
>
>
>
> 1) IBM is recommending SAME (Stripe across all the 46 LUNs) + 2 separate
> LUNs for online redo logfiles
>
>
>
> 2) IBM is recommending 32 MB Stripe Unit size across the 46 LUNs using
> Volume Manager.
>
> NOTE - Each underlying LUN has 8 Disks (Hardware Raid 1+0 with Stripe
> Unit Size 64 KB - This is NOT changeable)
>
> Qs. Any feedback on impact of 32 MB Stripe Unit Size(across LUNs) on
> Performance of OLTP / Batch Transactions?
>
>
>
> For now we are also considering doing a Comparative benchmark of
> Performance of 32 MB versus 64 KB Stripe Unit sizes across the 46 LUNs.
>
> NOTE - We may NOT be able to do an exhaustive comparison. Hence any
> similar experiences would help very much.
>
>
>
> NOTE - In a previous VERY Small benchmark on a few CPUs machine & a Very
> Small Storage Box having just a Few Disks with single Software
> Striping(NO Hardware Striping) , Performance of our Application's Batch
> Runs was VERY POOR for Stripe Unit Sizes of 512 KB, 1 MB, 2 MB.
> Performance was Good for Stripe unit Sizes of 64 KB & 128 KB.
>
>

Chris Dunscombe

www.christallize.com

--
http://www.freelists.org/webpage/oracle-l