Looking for ZFS/ zvol config suggestions

[guyisit]

Hi all,

I have a SuperMicro SuperStorage 6028R-E1CR24L server that I'm trying to figure out the best storage config for my existing hardware. The load will be VMware virtual machines served over iSCSI via the 10Gb NICs.

• 2x quad core Intel Xeon E5-2623 v4 @2.6GHz
• 128GB DDR4 ECC Registered DIMMs
• LSI SAS3008 HBA
• Quad 10Gb Intel NIC
• Quad 1Gb Intel NIC
• STORAGE
• 6x 800GB Intel SSD DC S3610 (rated 3 DWPD)
• 18x 2TB Seagate Enterprise 7,200rpm 3.5" HDD (512e)

So I initially setup the storage as a single giant volume comprised of 3 RAIDz2 arrays striped together (the HDD) with a 4 SSD stripe L2ARC and a 2 SSD mirror ZLOG.
This machine will have snapshots replicated to a second machine (with similar specs, though not quiet as beefy.)

I figure before I throw production VMs on the volume, I should see if the hive mind has any better thoughts as far as the volumes go. I appreciate everyone's time and input.

 

[Evi Vanoost]

Choose mirrors over RAIDZ2 unless you don't need the IOPS. You should try to get 4K hard drives instead of 512e just for the future or go 2.5" if you need a lot of storage in little space. You can still backup to a RAIDZ2 given backups are streaming loads, that way you get enough space for backups and snapshots without sacrificing performance on the primary storage.

As far as the ZLOG, you can get a couple of smaller SSD's since you only have 128GB of RAM, your ZLOG will never grow beyond a few tens of GB, perhaps the write-enhanced version of the Intel DC SSD's (S3710 or if you have money for a DRAM-SSD).

Having 4x800GB in L2ARC means it will gobble up a little more of your RAM, given your workload is just VM's, that may not matter since for you it's probably better to be in L2ARC and have less ARC than a smaller L2ARC, but again, that depends on your workload.

 

[guyisit]

Thanks for the feedback, Evi. The hardware is what it is at this point (was originally for a different software platform that "didn't work out".)

For the mirror, should I just do a bunch of two drive mirrors, striped together?
And for the ZLOG, should I just not have one? I could use those SSDs in the backup system, I suppose.

 

[Evi Vanoost]

Yes, two drive mirrors (3 drive if you're very neurotic about your data). For the ZIL, it's better to have 2 in mirror, but 800GB is a bit of waste for ZIL so if you need those drives, it's may want to buy 2 smaller DC's to save some money and re-use these 800GB. But if you only have 1 ZIL, and your power goes out and the system comes back without the ZIL, you'll lose some of the most recent writes. Too much ZIL doesn't matter, you just won't use it.