DL385 Simplex / Duplex question

[Clive Crocker]

Hi

I have a DL385 with 2x72Gb in bays 1&2 as Array A (RAID-1) and 2 x 146Gb in bays 3&4 as Array B (RAID-1 also), using embedded SmartArray 6i (with battery option).

I have installed the Duplex SCSI terminator etc. The system is running fine. However, I wonder if I have done so in the optimum way...? At present, Array A has it's own SCSI channel, and Array B has it's own channel.

Would I be better (would it even work?) to have 1 of each drive in bays 1 & 2, and the other of each in bays 3 & 4, so that both both arrays share both channels? I can see that this may help in the event of a channel failure, and possibly performance may be better.

On the other hand I can see advantages in having a SCSI channel dedicated to each array...

Can you offer me any guidance?

Thanks

[Felipe Martinez]

Clive:

Your current configuration is correct. You can make arrays only with disks on the same channel.

[Oleg Koroz]

Not quite right - you can make array across channels as long all channels belong to same array controller.

For your Question if you can split for each array utilize both channels in case one channel fails, its extremely rare occasion when one channel fails, more likely you will get Array controller failure rather than one channel.

Present Configuration would be more beneficiary for you in case if in the future you run out of space and you can migrate from RAID 1 on the Channel 1 to RAID 5 with 3 or 4 drives.
Or move second Part of Duplex to the optional PCI Array controller.

[Clive Crocker]

Thanks for both updates; I will leave as it is at present as it sounds more common.

I understand it's more likely to have complete controller failure than 1 channel failing.

Thanks also for noting the space availability with RAID-5 instead of RAID-1. However, it's not a problem at present. My server will be running SQL 2005 and I'd like to keep log and data files on different physical disks as well as having good write performance so I think RAID-1 is better for me at persent.

Regards