S Glasoe wrote:
Yeah, that seems to be a good option. Unfortunately the Storageworks controller does not support mirrors built on top of RAID5 sets,
Drop the parity on the RAID5 and you have a RAID10. What's the point of wasting the time calculating parity? You lose space with RAID5 mirrored to another RAID5 versus same number of drives in a RAID10. Same number of points of failure also. RAID10 baby!
But with a RAID15 (two mirrored RAID5s) I can survive a two-disk fsilure - one in each RAID5 or two in one RAID5. That doesn't quite work with a RAID10 array. It'll take any number of failures in any one stripe, but if two failures occur one in each stripe, I'm dead. Or am I missing something?
RAID0 issues too. Any one RAID5 array goes down = no data. Are you thinking a RAID5 array is all on the same controller channel or are you thinking of spreading a RAID5 array across multiple channels on the same controller?
There are two controller with each six SCSI channels, but only one controller will be visible at any one time.
Still, software mirroring of two hardware RAID5s sounds like a pretty good way to go.
Across controllers?
No, it would be on the same controller. /Per Jessen, Zürich