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Multi Sized Disks in RAID-Z2

Posted: 16 Feb 2015 18:56
by Impulse1
I've decided to upgrade my NAS from a RAID-0 UFS setup to a more secure RAID-Z2.

I ordered 4 x 2TB WD Red drives while away for work so that they would be here when I finally got home. I currently have 2 x WD Green drives. And here's my problem, I thought I had 2 x 2TB Green drives, but upon returning home I see that I actually have 2 x 1TB Green Drives...

I see my options as follows:

1. Setup a RAID-Z2 configuration using the 6 drives I have (4 x 2TB Red and 2 x 1TB Green) and accept that I'll be underutilizing the 2TB drives.
2. Go out and spend another $220 CDN and pick up 2 x 2TB Red Drives.
3. Buy a cheap 2-port RAID card and a 2TB Red Drive (Aprox. $160 CDN) setup the Green drives in a RAID 0 and use them in the 6-drive RAID-Z2 with the other 5 2TB Red Drives. I don't even know if this is possible..

I'm strongly leaning towards option 1 for now, I currently don't require the extra 4TB that I'd be missing out on, and I'll keep an eye out for sales on 2TB Red drives to replace the Green drives at a later time. However, when I finally do upgrade the 1TB drives to 2TB drives in the RAID, does it automatically resize appropriately, or will I be required to rebuild the RAID? Are there any issues in underutilizing the 2TB Drives?

Thanks for the help guys!

Multi Sized Disks in RAID-Z2

Posted: 16 Feb 2015 21:18
by b0ssman
You might have to create the array from the command line as the create command will normally exit with a warning about the unequal size. And yes the array can be resized when all 1 tb drives have been replaced. You will have to set an option to Auto resize the array.


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Re: Multi Sized Disks in RAID-Z2

Posted: 17 Feb 2015 00:11
by Impulse1
Thanks for the quick reply b0ssman!

Can that option to auto resize the array be set through the GUI, or is it something that has to be set during the array setup?

Re: Multi Sized Disks in RAID-Z2

Posted: 17 Feb 2015 02:30
by kenZ71
Yes, you will need to build the pool from the command line but it is easy. Make sure you specify 4k drives.

Once you find the larger drives on sale simply swap them in. Maybe consider buying 3 or 4 TB drives so you are not replacing all when your pool is near capacity.

Re: Multi Sized Disks in RAID-Z2

Posted: 17 Feb 2015 08:22
by b0ssman

Re: Multi Sized Disks in RAID-Z2

Posted: 19 Feb 2015 00:48
by Impulse1
Thanks for the help guys, I created the Pool using the command:

Code: Select all

zpool create -f Pool1 raidz2 ada0 ada1 ada2 ada3 ada4 ada5 
And it seems to have worked:

Code: Select all

nas4free: ~ # zpool status
  pool: Pool1
 state: ONLINE
  scan: none requested
config:

	NAME        STATE     READ WRITE CKSUM
	Pool1       ONLINE       0     0     0
	  raidz2-0  ONLINE       0     0     0
	    ada0    ONLINE       0     0     0
	    ada1    ONLINE       0     0     0
	    ada2    ONLINE       0     0     0
	    ada3    ONLINE       0     0     0
	    ada4    ONLINE       0     0     0
	    ada5    ONLINE       0     0     0

errors: No known data errors
How do I get this to be recognized in the GUI now under the Disk|ZFS section? Also, how do I ensure that the drives are specified as 4k drives as kenZ71 suggested?

Re: Multi Sized Disks in RAID-Z2

Posted: 19 Feb 2015 01:15
by kenZ71
To have the gui catch up I think you want to go to zfs | synchronize

For the 4k:
zpool Pool1 | grep ashift

If the result is 12, your good. If the result is 9 your drives will behave like old slow drives

Re: Multi Sized Disks in RAID-Z2

Posted: 19 Feb 2015 03:56
by Impulse1
Thanks kenZ71

I used

Code: Select all

zdb -C Pool1 | grep ashift
and got "ashift 12", so I'm all good there it looks. The synchronize is a great tool, took a while to find though haha.

My only problem now though is that I can't seem to Pools | Management configuration to apply. It is automatically filled in after the synchronize, but I can't apply the changes, I keep getting error code 1. I tried setting the mount point to /mnt during the Pool creation to see if that would fix the issue, but it hasn't.

Code: Select all

zpool create -f -m /mnt Pool1 raidz2 ada0 ada1 ada2 ada3 ada4 ada5

Re: Multi Sized Disks in RAID-Z2

Posted: 19 Feb 2015 04:07
by Impulse1
Never mind, I got it to work. when in doubt always try restarting... Wish I had done that a few hours ago!