On Jul 25, 2007, at 12:42 PM, Adrian Hall wrote:
For some values of "best", anyway, and for three disks it's about the only option. I would express the following caveats about RAID 5, though: RAID 5 will help you if you lose one disk, but only one. If you lose a second disk the data is gone. It behooves you to have some kind of monitoring in place so you're warned of a disk failure. This becomes more important the more disks you add, because the odds of one of them failing start to increase. This can be mitigated by adding a hot spare drive, or by using RAID 10, but these obviously increase the cost because you need more drives. RAID 5 offers good read performance but writes are slower, especially when writing lots of small files. For example, one external hardware RAID array I've seen benchmarked could write a single 1.6 GB file at 38 MB/sec, but dropped off to 0.06 MB/sec when confronted with lots of tiny (<20K) files. |