RAID 0+1 or RAID 5 - which is best?

machinist

machinist

machinist

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I'm looking to build a server that is tolerant to disk failure, but has best performance.
From what I've googled, RAID 0+1, is the best choice.

Does anyone have any real experience of these RAID configs? I'm looking for comments/thoughts please.

Thanks
 
Ive got raid 0+1 not sure its running 100% but thats my own issues, my freinds got raid 5 and its very slow writing slower than a standard disk so he says if you want i can ask him to do some HDtune benches and compare them against mine? it wont be very fair as we dont ahev teh same drives but will help you to get an idea.
 
Cool thanks for the info.
After a bit more reading it seems RAID 1+0 (RAID10), is quicker than RAID 5, and safer than RAID 0+1.
Think I'm gonna give that a try.
 
If RAID5 is set up using (motherboard) onboard RAID cont. the writes will be quite slow in comparison to using a (true) hardware SATA RAID card, as the motherboard onboard cont. is only a software implementation of RAID5, which means the CPU has to do all the parity calculations; whereas with a (true) hardware SATA RAID card, the chip does it, giving you good writes, ie. for a 4 dics RAID5 array, you will get writes equivalent to the writes from having 3 discs in RAID0...
 
It depends on what you mean by 'best'.

If you want maximum storage space from a given number of disks (storage = (n-1)*s, where n is the number of disks and s is the size of a single disk) and are less fussed about R/W speeds then raid 5. You will also ideally need a raid card with a didicated XOR processor or performance will be even worse.

If you want maximum speed then raid 10 but you only get (n/2)*s for storage.
If you want
 
Im running my raid 5 on my mobo (no space for a raid controller). Writes done seem to bad, but then again I dont write to it very often, its just there for storage of media. i get up to around 300mb/s read from 4 drives though (i know it could be much better with a raid card but meh, its good enough for the moment....except im running out of space AGAIN FFS)
 
If it's a server you don't usually require fast writing - so this is why RAID5 is quite often used.
Read performance is very good and the redundency in place means that any one of your drives can fail without data loss.

Also as said above you get more "useable" space with RAID 5.

4x 250GB HD

RAID 5 - 750GB useable
RAID 0+1 - 500GB useable
 
Yeah I'd go with RAID 5 and a dedicated controller card as others have said, gives the best balance of capacity, speed and redundancy imo
 
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