10 * 300 GB raid configurations on msa1500

[Joaquim Lopes]

Hello,

Having 10 * 300 Gb disks, what it’s the layout I should use, this question arouse from various contradictory opinions regarding “putting all the eggs in one basket” from a possible failed raid 5 with 9 * 300 Gb + 1 online spare or 10 * adg raid configurations.

This san will be used by 4 servers, file server, exchange, sql , iis. ( I have also 3*35 Gb for raid 0)


Possible configurations, give into account that the main purpose is redundancy balanced with space availability. Can I get some opinions regarding these layouts?

1º - 3 * 3 100 Gb raid 5 arrays with 1 online spare
2º - 2 * 4 raid5 and online spares
3º - 1 * 9 adg raid + 1 online spares
4º - 1 * 9 raid 5 + 1 online spare



regards,

[John Kufrovich]

Joaquin,

I wouldn't look at RAID configurations until determine your application sizing.
Take for example, Exchange,
How many users. Mailbox size. Version of Exchange.

SQL: Is this a transactional or data warehouse.

You have to think quality of service to your end users.

[Rob Leadbeater]

Hi,

Personally I'd avoid RAID-5 altogether and use RAID-1+0.

But then I've no idea what *your* data size is going to be, what level of performance you're expecting from the MSA and what level of redundancy you need.

If the MSA will be stuck at a remote office where people won't monitor it correctly, then disks in a RAID-5/6 may go unnoticed for some time. If all the physical drives are from the same batch there is a higher likelihood of them failing in the same time period, which can lead you to start searching for the backup tapes...

Hope this helps,

Regards,

Rob

[Joaquim Lopes]

Olá,

Regarding date size, it will be approximately 300 Gb for mail, 300 to sql(transactional) and the rest to file server. This will be in the main office and at this moment they have DAS with raid 5 .

RAID-1+0 this will to better performance but less space available (1/2) Iâ m I right?
Good point about the estimated failure time for all disks.

And about the choices 1, 2, 3 or 4 which you think is most usable for reliability and then space availability?

Regards

[Rob Leadbeater]

Correct. RAID-1+0 should give you better performance, but you will have less available space - with 10 x 300GB drives, you'll end up with 1500GB useable. (actually closer to 1430GB by the time you convert marketing to real GB).

Option 1
Usable space: 600 + 600 + 600 = 1800GB
You could lose up to 3 drives simultaneously.

Option 2
Usable space: 900 + 900 = 1800GB
You could lose up to 2 drives simultaneously.

Option 3
Usable space: 2100GB
You could lose up to 2 drives simultaneously.

Option 4
Usable space: 2400GB
You could lose 1 drive


Based on this, RAID-6 (ADG) looks like it might be a good idea, however it would be wise to do some performance comparisons first.

Cheers,

Rob

[Joaquim Lopes]

ola,

and in terms of reliability, whatâ s your bet? :D

one raid or 2 or more raid? (The concern here, is that the failure of one raid could bring the entire msa down)

regards,

[Jorge Cocomess]

I agree with Rob. As for the Exchange server, it's all depending on your environment. As for our, our Exchange db is almost 1.0TB. Therefore, we have one msa1500 dedicated for it and used mainly RAID 1+0, plus 1 spare -- We learned form the hard way by having RAID5....That was a no, no.

Make sure you configure this volume as "Dynamic" disk, rather than basic disk.

Jorge

[Glenn N Wuenstel]

Joaquim,
Another thing to think about here is that you would want to separate the Log LUNS from your DataBase LUNS.
I'd recommend using RAID 1+0 for DBs and Logs and RAID 5 for your file shares.

2 x 300GB RAID 1+0 Logs (Exchange & SQL)
4 x 300GB RAID 1+0 DBs (Exchange & SQL)
3 x 300GB RAID 5 Flat Files
1 x 300GB Hot Spare

In reality though I'd recommend a smaller drive pair for the Log LUNS as most of that space won't be needed but you still want to put them on a separate drive from the DBs for performance. If you look at the various sizer tools HP offers this can help...
http://h71019.www7.hp.com/activeanswers/Secure/71110-0-0-0-121.html

Glenn