Hai Boys

[Klendathu]

Originally Posted by Samoht [You must be logged in to view images. Log in or Register.]

well it depends on a few more factors than just number of drives. software raid or hardware controller? what kind of uptime do you need? what is the size of the raid?

if you're actually limited to 3 drives, nowadays you could realistically put the drives into a raid 0 and back up to cloud/colo and not give a crap. you'd still have redundancy, but you'd be working off of remote copies for a few hours if you lost your local.

and raid6 is the answer for 4 drives. it's same drive count as a raid5 with a hotspare. same capacity, too, with better read performance, but sometimes worse write performance if you're running software raid or have bad cache/controller. you'd have the redundancy for two concurrent failures, something a raid10 or a raid5 with a hotspare can't guarantee.

I'm with you on a lot of that. The controller makes a big difference. Uptime\amount of time to rebuild the RAID set, all of that is A+ info. And RAID 6 is superior when it comes to rebuild time, especially when it comes to large disks (1TB or more).

It's been my experience that RAID 10 is far better for databases, performance-wise. RAID 50 isn't bad either, but I'd go 6 before 50 cause the redundancy+rebuild time gain is better than the performance gain. IMO anyway. 6 gains a lot more....efficiency (for lack of a better term) the more disks you have in it. You wouldnt go wrong, either way.

Anyway, enough derailing the thread with nerdy shit. Bring back the trannies.

[Samoht]

Originally Posted by Klendathu [You must be logged in to view images. Log in or Register.]

RAID 10 is far better for databases, performance-wise.

for reading, yes. it can read the same data from two different locations at the same time without calculating the parity/XOR, but the write time is going to be slowwww because it's writing/striping the same exact thing over two sets of drives.