Optimal controller/drive layout for pool of mirrored vdevs?

[amurray]

Hello!

Right now in my test-build machine I have two zpools. The main one is six WD Reds arranged as three mirrored pairs, with a caching SSD for ZIL/L2ARC partitions. The secondary pool is three older SATA II drives in a stripe, used to store extra backups.

The six Reds are all connected to the motherboard's six on-board SATA ports (AMD 990X chipset) and the SSD and other three drives connected to a Highpoint 640L controller (4 ports, no hardware RAID shenanigans).

Everything is performing great, but I can't help but think that having all six Reds on one controller is a 'bad idea' and either way I'll need more ports to grow the Red pool (ie. add another mirror vdev.)

So, I have another Highpoint 640L SATA controller coming.

My question is what the optimal arrangement of controllers and drives would be?

I'm thinking:
Mirror 1-drive A -> controller 1
Mirror 1-drive B -> controller 2
Mirror 2-drive A -> controller 1
Mirror 2-drive B - > controller 2
Mirror 3-drive A -> controller 1
Mirror 3-drive B - > controller 2

...and put the SSD and the stripe's drives on the motherboard's controller? Or can/should I spread the stripe's drives out across the controllers as well? Will spreading a ZFS pool's disks across multiple controllers (of the same model) cause performance/reliability/timing issues?

What are the general rules for arranging disks across multiple (non-RAID) controllers for ZFS pools (or specific types of vdevs?) I haven't been able to find any ZFS/FreeNAS/FreeBSD specific requirements anywhere, so any advice/guidance would be appreciated.

Thanks!

AM

 

[cyberjock]

There's no rules for this. Big picture, if you want to spread them out over the controllers you certainly can. The bottom line though, if a controller fails it'll probably crash the box, so you didn't save yourself much. ;)

All you have to do is make sure you aren't bottlenecking yourself someplace that actually matters and ignore everything else. Your bottleneck is almost guaranteed to be your LAN ports unless you plan to go 10Gb.