DL 580 G5 Array Config

[Andreas Obermayer]

Hi all,

I have an DL580 G5 Server with two P400 Controller, so I am able to connect my 16 Disks, but I am not able to create one Raid 5 with all 16 Disks.

Does anyone know if it gives a solution that I can create a Raid over all 16 Disks?
I know with a P800 would it be possible, but not supported, because there you have to connect two internal cables of one (disk) backplane on the two external connectors of the P800 ;-)

Did anyone know if it gives a SAS Expander for this Server that I connect all 16 Disks to one P400 or someting similar?

Many thanks in advanced
lg
andi

[Battou]

Hi Andreas,
On the DL580 G5 you cannot create a Raid 5 with all the 16 Disks, the only servers that have an expander board are the new G6 servers but the expander is not available for the DL580 G5 =( .

Best Regards,
-Battou-

[TTr]

As far as I know the two disk cages in the 580 are isolated in terms of cabling and you can not daisy chain them into one bus. Also I would not create a raid5 with 16 disks in it driven by a raid card, it would have very slow i/o. I don't see the benefit of 16 disks in raid5 (15 data + 1 parity) other than one huge logical disk (or maybe there is another reason that you need to explain).

If you create two separate LUNs on each cage can you combine them at the OS level? What OS is it?

[TTr]

Actually there is a sas expander for the P410. http://h18004.www1.hp.com/products/servers/proliantstorage/arraycontrollers/sas-expander/index.html

As I mentioned you can end up with i/o contention running 16 disks on 8 SAS ports if all 16 are bound in a raid5 array. The controller has to collect the raid5 stripe from all 15 disks to recreate the i/o and pass it to the server.
Refer to my reply in this post as well about sas expanders http://forums13.itrc.hp.com/service/forums/questionanswer.do?threadId=1354168

[Andreas Obermayer]

hi,

thanks for your answers.