IronWolf
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ssampier said:RAID 1 can be slow and it's only a benefit if one of your drives fail; don't think about doing it as a backup. RAID 0 you are putting all your eggs in one basket. Any drives fail; your data is toast. RAID 5 is better for speed and redudancy, but I haven't seen it on too many consumer systems.
RAID1 can be slower than a single disk - just because the same data needs written to two locations. But the single disk doesn't provide any fault tolerance.
RAID5 isn't really high performing in all situations. It is just a way to get a large amount of fault tolerant disk space at a reasonable price. RAID5 sucks at random writes, does well with sequential reads. Rebuild times can be quite long with RAID5 and you suffer a fair amount of performance impact while the array rebuilds - though a lot of this varies on the size and speed of your disks.
Here is a link comparing RAID1 and RAID5 with no cache hits:
http://blogs.sun.com/mrbenchmark/entry/raid_1_vs_raid_56
RAID1 smokes RAID5 in every test - sometimes quite substantially.
Now controller cache can have an impact on the performance hit RAID5 takes, there are some graphs later in that series that do show that.
If you want fault tolerance and performance, looking at a RAID10 solution is better - but certainly not practical for consumer systems.
In either case, there is a good bit to know when tuning I/O subsystems - including knowing how the disk array is going to be used. Most of which is probably overkill for a home PC...
