topic Re: hp p400 array controller in Disk Enclosures

hp p400 array controller

kjcr33 — Wed, 17 Dec 2008 16:58:05 GMT

I have a DL 380 G5 with 2 P400 controllers. The way the server is cofigured all drives are on one controller. 8 physical drives. What I want is 4 logical drives

2 logical on 1 physical
1 logical on 3 physical
1 logical on 4 physical

My question is is it more optimal to split the drives on the controllers?

Also should you keep logical drive on drives in the same port (cage)

thanks for your time.

Re: hp p400 array controller

marsh_1 — Wed, 17 Dec 2008 17:30:46 GMT

hi,

yes i would split the drives between the controllers, you should gain by splitting the workload up. each controller can only see it's own physical drives and logical units have to be made up of the physical drives each controller can see, if you have more than one disk shelf attached to each controller this can help with redundancy in some circumstances, this is in the hardware , if you use software raid / mirroring software you could have a logical unit made up of physical or logical drives from each controller.

hope this helps

Re: hp p400 array controller

kjcr33 — Wed, 17 Dec 2008 18:09:05 GMT

thank you for your answer. On the P400 there is also 2 ports or cages. Are there any performance issues crossing the ports in a logical configuration?

Re: hp p400 array controller

marsh_1 — Wed, 17 Dec 2008 18:17:48 GMT

no , not as far as i am aware of and in the case of raid 1 volumes this would cater for shelf failure.

hope this helps.

Re: hp p400 array controller

kjcr33 — Wed, 17 Dec 2008 18:18:41 GMT

Thanks Mark. What's funny is that I just received a reply from an engineer that said to keep them on the same controller. Go figure! So on the controllers that I am using with 8 drives there is 2 ports (or cages) should the logical drives be configured within those ports if possible or does it matter?

Re: hp p400 array controller

marsh_1 — Wed, 17 Dec 2008 18:26:38 GMT

AFAIK it does not matter, i can't see why you would want to put everything through one controller when you have two ?

Re: hp p400 array controller

kjcr33 — Wed, 17 Dec 2008 19:51:48 GMT

I agree

Re: hp p400 array controller

marsh_1 — Wed, 17 Dec 2008 20:13:25 GMT

good luck with it - whatever you decide to do !