topic Re: Mirroring on same controller in Operating System - HP-UX

Mirroring on same controller

Rodney Hills — Wed, 20 Aug 2003 14:39:43 GMT

I have a new rp2470. I put in an additional Ultra160 scsi card attached to a DS2100 (4 disk drives). The rp2470 has 2 internal drives (aren't these Ultra160?). I need to allocate 12gig of storage and to have it with mirroring and striping.

My question is this:
Should I stripe on the first 2 drives of the DS2100 and put the mirror on the other 2 drives (traffic would then be on the one controller)?

Or-
Should I stripe across all 4 drives on the DS2100 and mirror on the 2 internal drives (thus distributing the mirroring across two controllers). The 2 internal drives are also being used as the root disk (vg00) and its mirror.

Preferably two controllers for mirroring is best, but I think the impact on my root disk is going to slow things down.

I have a Fast-Wide scsi controller (20mb/sec xfer rate) I could mirror on, but then that would be limiting the speed of the Ultra160.

Any thoughts on which configuration would provide the best throughput?

Thanks in advance...

-- Rod Hills

Re: Mirroring on same controller

Pete Randall — Wed, 20 Aug 2003 14:45:13 GMT

Rod,

Given that the two internals are already being used as root and its mirror, you would be well advised to avoid using them. You don't want to mix data in with your root VG, and you can't split the internal disks up between VGs, so I would leave root on the internals and put your data on the DS2100. In this case I wouldn't bother with striping either.

Pete

Re: Mirroring on same controller

Stefan Farrelly — Wed, 20 Aug 2003 14:56:33 GMT

I concur with Pete - keep vg00 and its mirror on the internals. Even if on the same controller a controller failure is exeptionally rare these days. dont bother with the FWD controller - its far too slow - only useful to tape drives or cd's nowdays. And keep all your data on the DS2100 - but I would stripe it at the lvm level as it adds more performance.

Re: Mirroring on same controller

Rodney Hills — Wed, 20 Aug 2003 15:26:59 GMT

Thanks for the input. I suspected I should stay away from the root disk on this.

I was wondering if the benefit in througput (by balancing the load) would be worth it.

But I think you are right in staying away from the root disk.

-- Rod Hills