I am planning to build a new computer and I wanted to get some advice on Raid5 and Raid 1+0.
Depending on your use of the computers storage.
RAID 0 Stripes multiple disks together, and such increasing capacity.
This is (in theory) the fastest raid setup.
No real limit to size. Apart from what your OS can address(close to 12TB on 32bit OS)
But there is absolutely NO SAFETY or fault tolerance. one disk dies, your entire raid dies, and the data stored on it as well.
(and believe me, restoring such data is EXPENSIVE)
RAID 1 Mirrors minimum two disk.
Write speed is quite slow. Read speeds are average.
Fault tolerance is one disk may die and data is still intact.
If more than two disks are mirrored, fault tolerance increases.
But capacity is limited to only one disk.
RAID 0+1 are combinations of striping and mirroring. Increased speeds and capacity.
And maintaining some degree of fault tolerance.
This setup is mostly limited to 4 disks. (more than 4 disks makes it VERY uneconomical)
RAID 5 same as RAID 0, but with certain advantages.
It needs at least 3 disks and it uses one disk for parity. Fault tolerance is one disk.
However if you are planing on running it with more than 10 disks consider RAID 6 instead.
RAID 6 same as RAID 5 but with two parity disks instead of only one.
Useless on raids with few disks. but becomes mandatory on large raids.
It will withstand a fault of two disks failing simultaneously.
Great when running a raid of 16 disks.
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After doing some testing. (on PATA and SATA disks)
Raid 0 and 5 increases speeds significantly until four or five disks are reached. But are sometimes maxed out at two or tree disks.
RAID 0 is by far the fastest raid configuration. (but it has NO fault tolerance)
Speed is limited by:
Average seek time, disk cache, internal transfer speeds, bus speeds, controller cache, internal controller speeds....
By raiding two 220MB/sec SSD disks read speeds of 400 MB/sec can be achieved.
But don't expect miracles from ordinary disks. 150 - 200 MB/sec can be achieved...
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To cut things short.
If you need speed and don't care about fault tolerances. RAID 0 is your thing.
If safety comes first, RAID 5 is recommended.
If you like me are completely paranoid by disk failure. Then RAID 6 is mandatory.
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As for RAID 0/1/0+1 (mirroring). i don't see no real use...
Striping two disks and then mirroring them with two more disks... it just wastes one disk and it will only tolerate one disk failure. (unless both disks of the mirror or stripe fails at the same time.)
By using RAID 6 and the same four disks.
still only two of them will represent the available storage. But it will withstand a two disk failure. maximum safety.
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EDIT: Adding a link to wikipedia article about RAID:
http://en.wikipedia.org/wiki/RAIDEDIT: Correcting some facts.
