HP 6300 EVA

danielanthony

danielanthony

danielanthony

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Hi,

I am getting a HP 6300 EVA with the 8xFC option and two shelves initially, one with 25x600Gb 10k LFF drives and another with 12x2TB 7.2k SFF drives.

I have 30 VM's which need about 200 IOPS and 250Gb disk space each, I'm running ESXi 4.1 so limited to 2TB datastores. How would it be best to split up the fast LFF storage?

Option 1) Create 5 x RAID5 disk groups with 1 LUN on each
Option 2) Create 1 big 25 disk RAID6 disk group with LUN's as near to 2TB as I can get them?

Thanks
 
You'll always want to put as many spindles into a disk/raid group as possible for best performance.

So with the 25 high perf disks you can do either raid 5 with a hot spare or raid 6, either will give you the required capacity.

I would recommend raid 10 or raid 50 for higher performance but I don't believe the this particular unit supports it?

To understand the IO available from the array based on the raid type penalty you would need to understand the split of your required IO into both read & write.

As for the 12 x 2TB use them for backing up VM snapshots onto ?
 
Like a lot of people I think you've misunderstood slightly how an EVA works if you're trying to get the best performance out of it :)

You create disk groups first, which basically creates an EVA virtual RAID on those disks, for best performance (and also simple growth) add all disks of the same type into a single Disk Group (iirc you get to choose the redundancy level - 1 or 2 disks which you get from the inherent underlying EVA virtual RAID).

Then you create LUNs which have the "normal" RAID levels - just a note - in EVA Terms RAID 5 is essentially RAID 50 and RAID 1 is essentially RAID 10 because your underlying EVA disk group is already a striped array (with reserved space per disk and distributed mirroring to give the multi drive redundancy).

For your I/O requirements I'd suggest your Option 2 as the best performing option, if you can afford the disk space I'd also suggest "vRAID 1" as you won't suffer any write latency from using 5.

I don't advise you use Multi-Extent Datastores in VMware, but that's your choice dependant on your requirements! If you can get upgraded to vSphere 5.0 your LUN size limit basically disappears!
 
Cheers guys, I've been using Dell MD sans for the last few months and this HP virtual raid stuff looks interesting. Btw, the 2tb drives are for file server storage, this doesn't need as much performance as the build/compile analysis stuff does
 
Be warned if you do create vRAID1 vDisks on your 25x600Gb 10k disks then you're going to end up with one disk unused. It's for that reason that the EVA best practice document recommends disk groups contain an even number of disks. If you're going with vRAID 5/6 then it's not an issue.

Also I've no idea if the EVA 6300 supports VAAI yet. If it doesn't then you're going to want to keep the number of VMs per LUN down to a reasonable level otherwise SCSI reservations can start to hurt I/O of all VMs sharing a LUN when you're creating VMs, taking snapshots etc.
 
Same EVA we are running here with ESXi 4.1 as well... but we only have 1 tray of 24x600gb :( - Also a single tray is 4 down 6 across so 24 disks.
 
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