Stripe size Recommendations

hi experts,

According to a published document from oracle website, it mentioned that 1M stripe size is recommended for optimal performance. Is this value still recommended for window platform ? My config is as follows :
 
- 9i RAC with OCFS on win 2003 32 bits
- EMC CX500 ( Raid 1+0 around Total 2X 146G FC disk drives )
- Dell PE Servers ( intel xeon x64 )

 
The EMC consultant recommended us to use 128K per disk since windows may not be able to handle the disk IO. Is it true ?  
Regards,
Nelson
nechanAsked:
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Duncan MeyersCommented:
The stripe size in this case refers to the stripe size written out to the discs on the CX500, and so depends on the number of discs in the RAID group. For example, if you have a 5 disc RAID 5 set using default options for the Bind LUN dialogue, your stripe size is: (128/2) * 4 = 256K (block size/2 to give bytes per disc * number of discs -1). For a 8 disc RAID 1/0 group, the calculation is similar: 128/2  * 4 = 256K (block size/2 to give bytes per disc * number of discs/2). To get a 1MB stripe size, you must increase the blocks per disc when you bind the LUN. So, if you were binding a LUN on an 8 disc RAID 1/0 set, then you would set the number of blocks (the stripe element size in the bund LUN dialogue) to 512 or 256K per LUN which may prove wasteful of disc space. I'd be inclined to accept the EMC consultant's recommendation unless you're after ultimate performance and you can accept some wastage of disc space.

Having said that, it depends on how heavily utilised your Oracle database is going to be. If it's going to get hammered, then you should consider this, however if it is not, you'll find that the Clariion's write cache will insulate your applications from what's going on at the discs. The Clariion also has a number of write optimisations that mean that a 1MB write will get written out to disc very quickly indeed as the array can coalesce the writes into one operation.

Have a look at this document: http://www.emc.com/products/systems/pdf/H1049_emc_clariion_fibre_channel_storage_fundamentals_ldv.pdf. It gets into performance details amongst other things.
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nexissteveCommented:
You will find that 2003 sets it to 128k anyway.

The only way you will be able to change it is to NOT service pack your windows 2003 server. If you already have service pack1 on then your stuck with 128k block size.

I would check out Oracle themselves for more information.

Hope this helps

Cheers

S
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mcp_jonCommented:
You can still change tha Strip size with Disk Part, but you will have to clear your partitions !

How to use Disk Part " http://support.microsoft.com/?kbid=300415 "

We did this proccess in our Exchange Servers !

Best Regards !

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Duncan MeyersCommented:
Glad to be of assistance!
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