NAS drive configuration

[wesg]

I'm building an NAS computer powered by Ubuntu, but I'm trying to determine the best drive setup for value and reliability.

I have a 750GB drive, and intend on purchasing one more drive when I build the computer (probably 1.5TB) but I can't decide whether to use RAID 5 and maybe buy 2 750GB instead of a 1.5TB, or just buy the 1.5TB and use a script to copy important files. ANy suggestions? I want to limit spending, but still have substantial storage space.

 

[Sesshi]

FYI: You need a minimum of three drives to run RAID5 - and in any RAID configuration the drives need to be the same size. The 650Gb drives should be at the cheapest buck-per-gigabyte level right now.

 

[nanofrog]

FYI: You need a minimum of three drives to run RAID5 - and in any RAID configuration the drives need to be the same size. The 650Gb drives should be at the cheapest buck-per-gigabyte level right now.

But better with 4, as in a 3 drive RAID 5, there's no redundancy. Loose a drive, and you skip degraded and go straight to dead array.

 

[Flash SWT]

But better with 4, as in a 3 drive RAID 5, there's no redundancy. Loose a drive, and you skip degraded and go straight to dead array.

I'm no expert but I don't think that is correct unless I'm misunderstanding your comment. The minimum number of disks for a redundant RAID5 array is three. If a single disk fails the array will continue to operate with only two disks and no data loss. You will take a read speed hit when the array needs to rebuild data from the failed disk using the parity information though.

http://en.wikipedia.org/wiki/RAID_5#RAID_5
http://storageadvisors.adaptec.com/2007/07/10/effect-of-drive-count-on-raid-5/

 

[nanofrog]

I'm no expert but I don't think that is correct unless I'm misunderstanding your comment. The minimum number of disks for a redundant RAID5 array is three. If a single disk fails the array will continue to operate with only two disks and no data loss. You will take a read speed hit when the array needs to rebuild data from the failed disk using the parity information though.

http://en.wikipedia.org/wiki/RAID_5#RAID_5
http://storageadvisors.adaptec.com/2007/07/10/effect-of-drive-count-on-raid-5/

Oops, Right thought, but botched the numbers.