RE: OFA and Shared Storage

Well, you don't want to configure it such that all files are striped across all disks. Every array has a "Sweet spot" in terms of spindles-per-raid group, and most arrays start to degrade significantly beyond that point.

The notion of striping at an array level is a little questionable to begin with - hardware striping is usually less flexible than software striping, though the usual disclaimers about cpu utilization on your host applies.

It's funny you mention EMC as an example - the Symmetrix does not inherently stripe well. The only reason striped volumes on the Symm were created is because windows boxes could only see a maximum of 26 volumes over fibre channel (think about it...). With the emc "hypervolume" model where each volume was a mirrored copy of a chunk of disk (so was generally around 9GB), the only way to get larger disks was to combine hypervolumes to get metavolumes. Most UNIX customers were using software RAID to get larger volumes for management benefits and continue to do so today. As always, the clariion is a totally different critter - sorry if that's what you were referencing.

Also, I have seen every major storage vendor have arrays burst into flames and lose data - so keep those backups handy....

Thanks,
Matt

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Matthew Zito
GridApp Systems
Email: mzito_at_gridapp.com
Cell: 646-220-3551
Phone: 212-358-8211 x 359
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> -----Original Message-----

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

> Behalf Of Mercadante, Thomas F

> Sent: Monday, September 22, 2003 2:45 PM

> To: Multiple recipients of list ORACLE-L

> Subject: RE: OFA and Shared Storage

> 

> 

> In my opinion, SAN storage begs the question about whether 

> OFA makes sense anymore.  If you can configurte the SAN 

> storage so that all files are striped across all disk, then 

> everything is spread.  And if the SAN is mirrored, then just 

> why are we working so hard?

> 

> EMC SAN disk has such an incredible uptime, that worrying 

> about losing things like control files are (almost) a thing 

> of the past.

> 

> Tom Mercadante

> Oracle Certified Professional

> 


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