Which array configuration?

[Gerardo Aguilera]

Hi, I have a ML370 G1 with a Smart Array 221, 4 9 GB and 2 18 GB hard disks. I see two options:
1) Only 1 RAID5 array: 45 GB available and 27 GB wasted.
2) 1 RAID5 array with 4 9 GB disks: 27 GB available and 9 GB wasted and another RAID1 array with 2 18 GB disks: 18 GB avalable space and 18 GB wasted
Which one is better?
and what's better, one big disk at array level and let W2003 make logical disks or making 2 or 3 logical disks at array level?.
Thanks in advance!!

[Stuart Browne]

What exactally do you intend to do with the system anyway?

The array configuration is usually dictated by the role the server is going to play so you can get the best performance out of the disks.

That being said, to make a RAID5 array of all the disks is not really the best option (as it would just throw 9GB per 18G disk as all disks have to be of the same volume), so the answer is either the 2nd option (RAID5 over the 4 9GB disks, RAID1 over the 2 18's), or as you have an even amount, RAID1 over the 9's as well as a 2nd RAID1 over the 18's.

The whole point of RAID is the loss of available space in exchange for performance and redundancy.

If you don't want any loss, see if the SA221 has a RAID0 option (which is basically just adding all the little disks into one, but no redundancy).

[kcpant]

Hi Gerardo,

In your situation, if I would have some mission critical data, and an application software ; I would have made a RAID 1 of 18GB X 2 and a RAID 5 of 9GB X 4 disks. Other options depend on your requirements. You can also make 2 RAID 0 volumes if you don't care about redundency.

For your second question, I would like to make logical volumes on OS level, to keep the RAID controller's configuration matrix simpler.