RAID 1 or 5?

chez

chez

chez

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I have just added a further 2x500gb drives to my system for storage, in addition to the existing 2x500gb drives.

The current drives are configured in RAID1 for redundancy. Now that I have 4 identical drives, would I be better off configuring all 4 as a RAID5 array?

Any thoughts/opinions welcomed :)

Thanks
Chez
 
If you're using onboard RAID then RAID5 is not a good idea, there is no hardware support for calculating the RAID5 parity so the main CPU has to do the work. This results in fairly high CPU load and pretty poor write speeds - 15-20Mb/s. All RAID5 solutions should give pretty much the same read speed - 4 disks should be about 130-150Mb/s average.

If you want to use RAID5 then you really need to look at a dedicated controller card, the RocketRaid ones are good but not truely hardware RAID5. £100 will get you a 4 port card which will be capable of 40-50Mb/s writes. If you want the best performance though you're looking at £300-400 for an Areca PCIe 8x card, 8 ports and 100Mb/s writes.

If it's only for storage then onboard RAID5 should be fine as long as you're happy to wait on writes.
 
Hmm.. I think I may just go with 2x RAID1 arrays then.. Storage is cheap enough that if I need more, I can always throw more drives at it..

Thanks for the advice ;)
 
if you have 4 drives, then give RAID 10 a thought. This is my ideal config, but have yet to find the money for it! Its basically a hybrid of both RAID 1 and 0, where you have a stripe across multiple mirrors. You dont have any parity to calculate, so read and write speeds are excellent. Plus, you are protected against up to 2 drives failing (as long as they are in different mirror sets), as opposed to just 1 in RAID 5.
 
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