A question of RAID

[googlemad]

So we have 2 SAN units for our backup, one is now starting to fail a lot so the idea is to just shut it down and shove the drives from it into the working one to have one big SAN for backing up to, split into 2 RAID sets. (Or would it be better just having a single RAID set?)

 

There are 14 1tb drives to play with, so I was hoping to create 2 x 7tb RAID5 sets which would give roughly 2 x 6tb volumes?

 

At the moment the working unit has 8 drives in it configured as a RAID set, is it possible to bring this down to 7 without wiping all the data? The controller is a ARC-1260

 

Hopefully the above makes sense as RAID is something that starts to baffle me quite quickly!

Edited April 4, 2014 by googlemad

[Michael]

You'd have to wipe the array and start again to reduce it to 2 x 7TB.

 

If you can, set it up as 2 x RAID6 as this gives additional redundancy at the cost of 1TB.

[Rodan]

I'd probably advise against one big RAID set as rebuild times would be quite lengthy, impacting response time if a disk failed.

 

In fact depending on your backup window and weight/type of data you might even go for more than two RAID sets as you could then use a greater number of readers and writers (if your software allows) and minimise disk contention. If you really need as much of the 14TB as possible this may not be applicable.