On Thu, Feb 28, 2002 at 02:37:33PM -0600, Jason Lohrenz wrote: > It has 4 20GB SCSI HD's in it. > Currently it's setup so 3 of them are in a RAID-5 Configuration with the > 4th as a Hot-Spare (They are all hot swapable). > I've heard some cons against RAID-5, and that RAID-1 or other RAID options > are 'faster' and better. IE with above only 1 drive can go bad at a time, > with a max of 2, but only if the spare has been brought up completely > before the 2nd fails...etc.. whereas other implementations can have 2 go > bad at once have you, as long as they aren't each other's mirrors. Well, it's all a matter of tradeoffs... RAID 0 - Stripe set. Gets you all available capacity (80G) and the best possible speed, but if any one drive fails, you lose everything. Probably not what you want. RAID 1 - Mirror. Only gives you one disk's worth of space (20G), but your data will be safe just so long as one drive still works. RAID 0+1 - Mirrored stripe sets. Structurally, this is two RAID 0 stripe sets configured to mirror (RAID 1) each other. With 4 active disks, you would get 2 disks' worth of capacity (40G) and, potentially, some of RAID 0's performance boost. Can survive the loss of both disks in a single stripe set, but if a drive goes out in each stripe set, you're semi-hosed; depending on how you're controlling the RAID, you may or may not be able to shuffle the drives to give yourself a good stripe set and reestablish the mirror from there. Compared with your current setup, RAID 0+1 would have the same capacity, might be be a little bit faster, and would be able to survive some combinations of two-drive failures (but not all). Personally, I'd stick with the RAID 5, since it's more expandable and the odds of two drives failing in rapid succession are pretty slim (unless you let the system overheat or something like that). If you're worried about multiple drive failures, the first thing to do (aside from making backups) is to ensure that each drive is from a different lot; the minor variations in materials and QC seem to have a disproportionate effect on the drive's actual lifetime. As far as what performs best, all I can say there is that bonnie is your friend. -- When we reduce our own liberties to stop terrorism, the terrorists have already won. - reverius Innocence is no protection when governments go bad. - Tom Swiss