P4300 - 2x RAID5 on 1 SAN?

[AndyR_WEX]

Hi,

Recently purchased a P4300 G2 to use on a VMWare ESX environment. Original plan was to have each tray seperate (security/politcal reasons) and have each tray running a single 8 disk RAID5 array totaling 2.8TB each.

All good.

But, one of the teams has now requested that 1 tray be split to form 2x RAID5 arrays of 4 disks each.

Is this even possible? I dont have any data on it yet so am OK re-installing but when I do a reimage there isn't an option to pick the array sizes. I notice there is a RAID1/0 at 32GB and the rest is RAID5 so assume the RAID1/0 is the SANIQ software.

Is it as simple as creating the arrays first in the controller to be 2x RAID5 and then let SANIQ install from that?

Thanks,

Andy

[Mark...]

Hi,
NOT supported / recommended to change the h/w RAID config of a P4000 SAN. You can change the RAID level from the CMC but - as far as I know - to try and change how the h/w RAID is physically configured is just not supported.
The SAN/iQ install will automatically config the h/w RAID and there is NO option in the install (not the one I have done/tried) that allowed you to alter/modify during the install.
As I said you can alter the LEVEL (5 or 10) but not the layout/config of the disks.
Network RAID is done from the CMC. However being as you have stated that you are using the P4300 seperately then you will be only be able to use Network RAID-0. If you put the two nodes together in a cluster then you will be able to use Network RAID-0 and 10 to create volumes.
Mark...

[IainS]

I think you are kind of missing the point of how the SAN is intended to be used. Essentially it takes away a lot of the low level control intentionally, so you can only apply raid to the entire node. If you want to do different RAID then you have to do it to another node (but probably shouldn't because these things are meant to be clustered together).

Also you are losing a lot of redundancy by running the nodes separately, and theoretically performance also (Although I am having problems myself getting multipath I/O to work with good performance to two nodes).

If you really wanted to be able to control RAID to that level you might have bought the wrong thing. Something like a dedicated server running StarWind or similar may have been a better choice.

[AndyR_WEX]

Thanks guys.

No thats all fine. Beleive me, I totally agree with what your saying as when we spec'ed the P4300 for us, everyone agreed we would run it with both trays in RAID5 and then Network RAID the two together as they are designed to run, and how I've used them in the past.

Its only since I've installed them that some of the departments have changed there mind, and wanted the SANs separate. Stupid decision, I protested but was overruled.

Now they are protesting the single RAID5 on the tray even though I told them, and showed them the spec they agreed to but they want it changing. I told them its not supported by they started saying thats what they want because of old school thinking on there part. I just needed something to backup my claims so thought I'd post here.

Thanks for your helps guys. I'll go bang my head against the wall with the people here again :)