First FreeNAS and some ZFS/RAID questions

[Unas]

Hi comm,

i'm new to FreeNAS/FreeBSD and i have some questions mainly regarding the ZFS Filesystem and RAIDZ2/1 and i would be really glad if you guys could help me out here.

First of all here's the hardware i'm planning to get:

Fractal Design Define R4
Asus P8B75-M LX Plus
Intel Core i3-2120T
be quiet! Straight Power E9 480W CM
2x G.Skill DIMM 8 GB DDR3-1600
Kingston SSDNow V300 2,5" SSD 60 GB
4x Seagate ST3000DM001 3 TB

Anything wrong with that? if not here are my questions:

I'm planning on using this setup for a RAIDZ2.
1. Is the system memory enough or i would i be better off using RAID5/6?
2. Is there any other downside of installing FreeNAS onto a SSD besides the "waste" of one HDD Slot?
3. I'm planning to add 4 more HDDs later on. Is this possible?
4. If not, is it possible with a RAID5 or RAIDZ1?
5. Is there a sabnzbd Plugin for FreeNAS?

Thanks a lot!

 

[warri]

1. Yes, the system looks totally fine.
2. Also you are wasting the SSD capabilities, FreeNAS is loaded into RAM on startup (so apart from writing config changes there is no access to the SSD at all).
3. Yes, you can either add a second, separate zpool, e.g. as RAIDZ1/2 or add a second vdev to the existing pool. See also http://doc.freenas.org/index.php/Volumes#Extending_a_ZFS_Volume
4. RAIDZ1 behaves basically like RAIDZ2. I don't have any experience with RAID5 though.
5. Yes, I think I saw it somewhere in the plugins section of this forum.

 

[Unas]

Thank you!

2. Also you are wasting the SSD capabilities, FreeNAS is loaded into RAM on startup (so apart from writing config changes there is no access to the SSD at all).

Oh, okay. It's indeed useless then. I read about using SSDs as ZIL/L2ARC device. Could you elabarote a little bit on that? Or link me somewhere where those two things are explained?

3. Yes, you can either add a second, separate zpool, e.g. as RAIDZ1/2 or add a second vdev to the existing pool. See also http://doc.freenas.org/index.php/Volumes#Extending_a_ZFS_Volume

The linked article says:

to extend a RAIDZ2 requires a minimum of four additional drives. The result is a RAIDZ2+0, similar to RAID 60 on a hardware controller.

So i'll have basically a RAID 60 then? A mirrored RAID Z2? Isn't it possible to just expand RAIDZ2 just for increased storage or would i have to disband the RAID for that?

Edit: Wait, the article answered my question i guess...

however, you can stripe a new vdev (and its disks) with the same type of existing vdev in order to increase the overall size of the ZFS pool.

So it's a bit counter-intuitive, but should work.

 

[cyberjock]

Thank you!

Isn't it possible to just expand RAIDZ2 just for increased storage or would i have to disband the RAID for that?

Read my guide(link in my sig).

 

[Unas]

Read my guide(link in my sig).

Very much appreciated. I sincerely hope someone tells you that you're a hero at least once per day. :)

So, what i get from this is, if i want to expand a zpool with more drives, i have to create a new RAIDZ2 to attach to the pool. In this case i would lose the capacity of 2 HDDs.
So basically if i just want to increase the storage for a pool i have to disband it and create it anew with all disks.
So, i guess i'll have to get all disks at once instead of adding them later.

Thanks!

 

[cyberjock]

Exactly! That's why I mentioned my guide.. you didn't seem to know that little(but important) concept :)