ZFS question - MD1000 with 14 drives

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vmfsx

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Apr 17, 2013
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So I was able to come across a Dell SAS HBA 5/E adapter along with a MD1000 array.

I've loaded it up with 8x 250gb 7200rpm and 6x 500gb 7200rpm sata drives.

I'm using the storage solely for an ISCSI datastore within ESXI 5.1.

My question is what is the best way to set up the array?

Right now I have 1 Zpool with 6 mirroed Vdevs as it was my understanding that this would provide the best performance for virtual machines. This is plenty of space for me, so I'm not worried about the storage cost of mirroring so many drives. I'm just looking for feedback as to whether or not this was the way to go. Oh and I'm using an Intel 320 120GB SSD for L2ARC.
 
My only concern is mixing the sizes in the pool. e.g. if you end up wih 4 250gb mirrors and 3 500gb mirrors, when the smaller mirrors end up close to full, new allocations will pretty much hit the 500gb mirrors and performance will drop (hard to say how much though).
 
Is this for home or business use? If it's for home use and you don't care much about losing a bunch of space you could try the following. It's far from the ideal configuration but I don't see why it wouldn't work.

danswartz said:
My only concern is mixing the sizes in the pool. e.g. if you end up wih 4 250gb mirrors and 3 500gb mirrors, when the smaller mirrors end up close to full, new allocations will pretty much hit the 500gb mirrors and performance will drop (hard to say how much though).
Click to expand...

To prevent this from happening he could just pair the discs up in a way that forces each vdev into being the same size.

ex.
6x Mirrored vdev's each comprised of 1x 250GB and 1x 500GB then use the last two 250GB drives as spares. You'd end up with about 1.5TB of space to play with.
 
that'll only work with 3 of the vdevs though, and you end up losing a significant chunk of usable space. not sure there's a good answer to that though :)
 
Nope, he has 6x 500GB drives and 8x 250GB drives. So he can actually make 6 vdev's using the method I described. It really is an ugly way of doing things though lol.
 
Heh. I divided once too many. 6 is what I did mean. Yeah, you're right... OOOGLY...
 
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