Quick ZFS question

iamwhoiamtoday

Limp Gawd
Joined
Oct 29, 2013
Messages
493
I'm looking into replacing my Windows file server with FreeNAS. This is in my home lab.

System is as follows:
2*L5520 Quad Xeons
48GB DDR3 ECC
Areca 1280ML (currently in RAID6, to be moved over to JBOD)
14*2TB HD's on the Areca card.
6*1TB HD's on the Areca card.
2*120GB SSD's on the motherboard

I want to have 14*2TB drives (probably in 2*7 drive RAIDz2 arrays) for my multimedia / library. (Areca 1280ML set to jbod mode)

I don't care about performance for the big volume. Plex doesn't exactly need crazy speeds.


I want to have 6*1TB drives in a mirror configuration (1TB usable space) plus two 120GB SSDs for cache to handle my hypervisors (probably iSCSI? maybe NFS? Dunno yet.)

I do care about performance for the hypervisor volume. Space isn't an issue. (1TB is more than enough)
This NAS is hooked up to an X448. A 10gbps fiber card is going from the server directly into the switch.
Realistically, seeing as how the hypervisors are all hooked up via two 1gbps ethernet cables, no one machine can max throughput.

With a potential for 20gbps (10 write, 10 read), I'd love to hear feedback regarding if the above is a halfway sane idea. (or if I missed something obvious)



Please note: This is for my home lab. The rational is "because I can" / "because I have the hardware," not for any attempt at sanity.
 
Last edited:

zrav

Limp Gawd
Joined
Sep 22, 2011
Messages
181
I want to have 14*2TB drives (probably in 2*7 drive RAIDz2 arrays) for my multimedia / library. (Areca 1280ML set to jbod mode)
You'll hear the recommendation to prefer a 2*6 raidz2 configuration. You'll also want to check this out.

I want to have 6*1TB drives in a mirror configuration (1TB usable space) plus two 120GB SSDs for cache to handle my hypervisors
...
I do care about performance for the hypervisor volume. Space isn't an issue. (1TB is more than enough)
For sake of write IOps you'd be better off with two three-disk mirrors or three two-disk mirrors.
 

timta2

[H]ard|Gawd
Joined
Feb 3, 2010
Messages
1,393
Using that many 1TB and 2TB drives doesn't seem very efficient these days, from a size to electrical use standpoint. Hopefully your rates are low. :D
 

danswartz

2[H]4U
Joined
Feb 25, 2011
Messages
3,693
It's even more important for read iops, since zfs will load balance reads across all members of a mirrored vdev.
 

iamwhoiamtoday

Limp Gawd
Joined
Oct 29, 2013
Messages
493
Gotcha. So if I went with three two-disk mirrors, both read and right would be pretty good, and then I can use the two SSD's for caching of reads on top of all that?
 

spazoid

Limp Gawd
Joined
Jun 16, 2008
Messages
289
If you have 48 GB of RAM in the machine, you'll have a huge ARC. I doubt you'd ever see any hits on your L2ARC devices, so they're basically just wasting ARC for the L2ARC table.

I would either ditch the L2ARC and monitor the ARC hits - if you have lots of misses, an L2ARC device might make sense, or use the SSD's for your hypervisor datastore if they're big enough.
 
Top