Re: OCP Question

In article <3B30D525.7DA10A60_at_attws.com>, Daniel.Morgan_at_attws.com says...

>Which brings up an interesting question. What do you do when the sys
>admin stripes multiple disks? Are they on different physical drives? And
>can you tell.

Well, hopefully, he's not doing that without coordinating with you first - at least he shouldn't be. Physical layout design is usually one of the longer meetings that I have with dbas. They usually start out something like this:

DBA: We want one disk on 200 controllers each under a different volume group.

Me: Well, you can't have that - neither an HP nor a SUN support 200 controllers. You can have 12 controllers with 10 disks each...

Let the negotiation begin...

<war story>
While supporting DBAs that were supporting upwards of 600 gig data warehouses, I finally convinced one of the dbas with a more open perspective that striping all tablespaces and indexes together across all 120 disks would provide better performance. The logic is that the chances of two I/Os hitting the same disk simultaneously are small. Even if they do hit the same disk simultaneously, they'll separate almost immediately as their respective I/O paths take them off in separate directions.

Not long after that, I saw a white paper from Oracle on VLDBs suggestion that exact layout. Felt pretty good about that one... </war story>

Doug

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Douglas K. O'Leary
Senior System Administrator
dkoleary_at_mediaone.net