Just for a practical scenario, here's the machine I have at my home. The front has four hot-swap drive bays, backed by a 3ware 4 port controller (IIRC a 9500 series). Two drives form a RAID1, which is where everything is kept. One drive is a hot spare. The fourth drive is a backup drive; my /home is on an xfs filesystem, so I use xfsdump to back that up, and store it on the fourth disk. Since it's hot swap, I can periodically remove the fourth drive and replace it with an empty disk; I can then store the old drive ''safely'' somewhere (if I were smart I would take it to work, but I haven't been smart yet). Now, to be fair, my storage needs are quite small: /home is only about 100GB (and is only 60% full). Obviously for storage at the multi- terabyte range you'll need more disks. --keith -- kkeller at speakeasy.net -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 197 bytes Desc: not available URL: <http://lists.centos.org/pipermail/centos/attachments/20091110/1ad5e635/attachment-0003.sig>