John R Pierce wrote: > raid50 requires 2 or more raid 5 volumes. > > with 4 disks, thats just not an option. > > for file storage (including backup files from a database), raid5 is > probably fine... for primary database tablespace storage, I'd only use > raid1 or raid10. RAID-10 has only one perfect application, and that's with exactly four disks. It can't use fewer, and the next larger step is 8, where other flavors of RAID usually make more sense. But, for the 4-disk configuration, it's unbeatable unless you need capacity more than speed and redundancy. (In that case, you go with RAID-5.) RAID-10 gives the same redundancy as RAID-50: guaranteed tolerance of a single disk lost, and will tolerate a second disk lost at the same time if it's in the other half of the RAID. RAID-10 may also give better performance than RAID-50. I'm not sure because you're trading off more spindles against more parity calculation with the RAID-50. At any rate, RAID-10 shouldn't be *slower*.