Which Raid do I Go?

[alison gates]

Hi,
I have received several Netservers LH 3000 to setup ??? I???m planning to use the NetRaid Hardware Raid (previously I had used Microsoft software Raid on (Netserver LH Pro) - I'm trying to determine the most efficient Raid Configuration.
Each server has (6 HDD) and will be used as either a file, web or application server.

I noticed that many users (in the forum) are configuring their Netservers with only one array (RAID 5). Is there any concern about system performance using only one Raid spanned across all ( 6 HDDs)?

Would users recommend a creating two arrays. One array (RAID 1)- (2 HDD) for the OS (system partition + a second array for data (Raid 5)- (4 HDD) or is this configuration now obsolete?

Also for the web server I was considering only Raid 0 because no data is on the server ???- the data is on an application server.

Thanks

[harry d brown jr]

Alison,

What OS are you using? Do you plan on having your OS on a non-raided disk, and then just use mirroring?

live free or die
harry

[Vincent Farrugia]

Hello,

Regarding RAID, no RAID configuration is obsolete, as long as it does what you want efficiently :-)

RAID 1 provides mirroring... It's safe, fast on read and write. RAID 5 is disk striping with parity spread across drives. The advantages of RAID 5 are the lower overhead costs with respect to RAID 1 (20% [for a group of 5] instead of 50%). Disadvantages is that read and write are slower with respect to RAID 1, and slower to recover. It depends what you want, really.

Regarding RAID 0, it's disk striping... it does NOT provide data protection. In the sense that if a disk fails, you lose ALL the data in the RAID 0 group, there's no way to recover. Whereas, if you have RAID 1 or RAID 5, you have all the data if a disk fails.

HTH,
Vince

Now it's up to you what you want to do... Your idea of doing mirroring on the OS disk and RAID 5 for the data disks seems to be a good one, but it depends on the speed you want data to be accessed (remember RAID 5 slows down read and write transfers).

[Gregory Hostettler]

Well, if you want to get max performance as well as redundancy, you can go to RAID 10.

This means that you can use 3 disks in a RAID 0 array, 3 others on a 2nd RAID 0 array, then mirror both arrays. This gives nearly the speed of striping AND the redundancy of mirroring.

There is also the RAID 15 option: 2 RAID 5 arrays mirrored, for maximum security and lowest performance. A cost for everything...

Anyway, if you plan to use Oracle (or any SQL RDBM) you should avoid RAID 5 as this impacts greatly on perfromance.

Now the point: I do not know if LH3000's support RAID 10 or 15. Just check if you can

a) have two halfes for your 6 cages (I think it is possible from an HWD point of view)

and
b) If the embedded NetRAID controller allows you to do so.

Hope this helps partially