On 3/29/06, Per Jessen
Greg Freemyer wrote:
I did not read all of the responses, but somewhere along the lines you said it was a HP Storage Works box. And some of the responses did not seem to understand raid all that well.
Hi Greg,
yep, it's a StorageWorks box. Not sure what the exact model# really is.
I'm certified to design Storage Works raid setups, so if you post details such as the array model number (HSZ80? HSG80?), # of controllers, # of shelves, # of disks per shelf I can give you more feedback.
Dual HSG80, 4 shelves, 6 disks per shelf.
The next step in higher reliability is to move to 3-disk mirror sets. ie. each of the 3 disks have exactly the same info. This is still called RAID 10, but now you will have 7 3-drive mirror sets all striped together with 3 hot spare drives. You can obviously survive a 2 drive failure.
That's one option I've somehow completely managed to avoid ... thanks for mentioning it.
HTH Greg
Yes, it did, thank you very much Greg. Now that you're on-line anyway, here's something I've been pondering - I have a 2nd SWKS box, except this is an older model with dual HSZ70 controllers. I'm fairly certain one box will be plenty, but I can't help thinking if this 2nd box could be hooked up to the first - sort of as a BA370 extension cabinet? I'm guessing I would need to remove the controllers.
/Per Jessen, Zürich
I'm not positive, but I'm pretty sure the shelves for HSZ70 unit should be compatible with the HSG80 unit. You should be able to check the shelves model number. IIRC, an HSG80 controller can drive 6 shelves. You should just be able to plug the SCSI cables that currently run into the HSZ70 controller shelf into the back of the HSG80 controller shelf. To be honest it has been a couple years since I worked with the HSG80 line (there out of production), but I think each shelf (or half shelf) is a single scsi bus. Then the drive slots correspond with the SCSI ID. You said you have 4 shelves that hold 6 drives each. I think these are split-bus shelves. ie. you have 2 logical 6-slot shelves per physical shelf. If with the HSZ70 shelves you have more than 6 of the split-bus shelves you should be able to buy a small PC card that connects to the back of the shelves and shorts out the 2 halves. Then each physical shelf holds 12 drives and counts as one of the 6 shelves your allowed. The more scsi busses the better the performance, so you don't want to convert the split shelfs to full shelves unless you can productively utilize the extra drive slots you gain. ie. With split bus shelves you can have 36 drives max (6 * 6). With full shelves you can have 72 drives max. (12 * 6). Also note that with a shelf failure, both of the split halves of a shelf can fail. So you want to be sure your mirror halves are not in the same physical shelf, not just not in the same logical shelf. Especially if you are considering RAID 5, you need to make sure each of the raid members is in a physically seperate shelf. HTH Greg -- Greg Freemyer The Norcross Group Forensics for the 21st Century