RE: Raid 1 vs Raid 5 for tablespaces

Depends on the storage array and your particular configuration. You could certainly create a bundle of RAID-1 luns/volumes and then create a larger concatenated volume across them, but you're very likely to end up with hotspots on the first few disks. Whether that matters or not is dependent on your data locality and the craftiness of your storage array.

Ooooor, use the LVM to create a striped lv across the exposed RAID-1 volumes. Create a dedicated VG for your raid-1 PVs and then build some striped LVs out of them. Then take a vacation in your RV. :)

Also, be aware that many many storage arrays have limitations on the number of RAID groups/volumes you can create, so you could easily be shooting yourself in the foot for the future by creating, say, 50 RAID-1 volumes when there's a limit of 64 raid groups on the array.

As far as RAID-5, I give all due respect and tithe to our BAARF leaders (the check's in the mail), but you might actually be able to do RAID-5. BUT - any array that can do RAID-5 but not RAID-0+1 makes me very skeptical of the quality of its RAID-5 implementation.

What kind of storage array is this that can't do raid 0+1?

Thanks,
Matt

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Matthew Zito
GridApp Systems
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> -----Original Message-----

> From: ml-errors_at_fatcity.com [mailto:ml-errors_at_fatcity.com] On 

> Behalf Of Schauss, Peter

> Sent: Tuesday, August 12, 2003 3:24 PM

> To: Multiple recipients of list ORACLE-L

> Subject: Raid 1 vs Raid 5 for tablespaces

> 

> 

> Our hardware people tell me that our disk array will not 

> support Raid 10. Given a choice between Raid 1 or 5 for my 

> tablespaces, which one is best?  This is Oracle 8.1.7 on AIX 

> 4.3.3.  The application will have a mix of read and write activity.  

> 

> Thanks,

> Peter Schauss

> -- 

> Please see the official ORACLE-L FAQ: http://www.orafaq.net

> -- 

> Author: Schauss, Peter

>   INET: peter.schauss_at_ngc.com

> 

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