> >>>>> "Brian" == Brian Fahrlander <Brian@xxxxxxxxxxxxxx> writes: > > Brian> I once asked a woman that worked at Veritas in tech support. > Brian> She said that on all these RAID arrays, loss of a second disk is > Brian> _ALWAYS_ fatal. I was stunned. > > Yup, she was right. > > Brian> I mean, a 30 drive array...and if the second drive goes out, the > Brian> entire thing is toast? > > If you choose to set up a single array with 30 drives in it, that is correct. > > Brian> There gets to be a point where this is a problem. In 1-5 disk > Brian> arrays, what are the chances of a second drive going out? Right: > Brian> almost nil. > > Brian> But when you have 50 drives in a special bay, the chances of a > Brian> second drive going out while you locate a vendor, find out it's been > Brian> obsoleted since it was installed, order a new part.... > > Exactly, so as the old joke goes when the guy tells his doctor it hurts > when he moves his arm, then don't do that! :-) > > Instead, keep the number of drives in any given array low. If you need > more space, look at getting bigger drives. If you need even more space, > consider "stacking" arrays (make a RAID 0 array out of as many 3-drive RAID > 5 arrays as you need to reach your storage requirements, for example). By > doing this you still are exposed to the risk of multiple drives failing at > any given time, but you reduce the exposure of any one array losing more > than one drive. > > Ed > -- > Ed Bailey Red Hat, Inc. http://www.redhat.com/ Depending on your RAID software you might also include a spare disk or two in the diskgroup. A disk fails and you replace it. You can have Veritas scream to syslog if a disk dies and you can schedule replacement. Not sure if any of the hardware raid solutions let you have spare disks, but seems possible. ciao! leam --
