My ZFS build - For VMware

M

ManateeMatt

Limp Gawd
Joined
May 27, 2009
Messages
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I am planning on building a Datastore server for my vCenter test lab that I have at work.

This is my specs:

Core i3 540
8GB ram
Supermicro X8SI6 motherboard
Supermicro 2U 8Bay CSE-825TQ-563LPB
8x 500GB Seagate 7200.12
2x Intel 320 G3 40GB SSD
1x Intel Gig nic for management

My questions are the following:

1. Is the i3 Beefy enought for this system?
2. 8GB ram enough? I think it should be but can go to 16 if needed
3a I haven't desided on an OS yet I was thinking freebsd as i am most familiar with that, but nexenta, solaris and openindiana all have newer ZFS versions
3b. I was thinking about installing on a flash drive but alot of these OSes dont seem to like usb sticks that much, so I was thinking about taking my 2 SSDs, putting them in a mirror, and then partitioning them up 10 GB for os, then the leftover 30 for L2ARC and ZIL. Or is that crazy, or should I get a bigger SSDs.
 
1. The I3-540 is beefy enough, but it lacks ECC memory support. ECC memory is highly recommended for ZFS. You don't need a lot of CPU for ZFS. Suggest you look at the lower-end Xeon x34xx and ECC memory.

2. More is better for ZFS, but 8GB should be fine as long as you don't turn on dedup.

3. ZFS best practice guide strongly suggests your ZIL not be partitioned or shared. Not sure how partitioning would affect the cache drive (L2ARC).
 
1. Probably okay, I think. I suspect network BW will be the limiting factor.

2. Probably okay - unless you use dedup, but you won't likely need that or want it with only an i3-540.

3. Sharing SSD's between OS and cache/zil can be tricky. Any of the OS based NAS/SAN will not benefit much from a fast root filesystem, since the code and such will be cache. OTOH, if you put the OS on a fast SSD, skip the cache device entirely, and it will automatically (I believe) put the L2ARC on the root pool, which is just what you want. Not sure a ZIL device makes a lot of sense unless you have a lot of small, random writes going on?
 
installing root on the SSD was mostly because its there already, not for the speed. I like keeping my OS drives, and my data drives separate. Because I have 6 sata ports and 8 sas ports in an 8 drive case, I could get a 2.5in hdd for root.

How much does dedup affect performance? It could be something that i might want to look at. Does it dedupe within the VMDK?
 
I assume because of one nic you aren't going to be testing any failover with Vmotion?
 
motherboard has 2 nics that will be put into a bond. that goes to 1 switch right now then each vm server has a minimum of 3 nics (odd number i know. 2 on board, and 1 pci-e nic)

Failover will be played around with on the vmware side. Right now all my nics are in vDS switch and then portgroups are made off of that for managment, fail over, and nfs.
 
No, dedup would be done on the zfs san/nas. It is pretty cpu intensive, and sucks a LOT of ram. A number of folks do not recommend dedup as being quite ready for prime-time right now...
 
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