Adding disks after ZFS?

[yojimbo]

Hi all, I've had a search but havent found anything obvious, I'm setting up a nas4free for the first time, I configure a 4 disk ZFS array with all disks in one virtual device with parity 1 etc etc. All good. I then add a new disk, this gets inserted at /dev/ada0, the list of disks is then incorrect, but worse in virtual device in zfs, it only shows disks 1-3, not 0, as it's noticed 0 isnt playing ball, I cant add #4 into the virtual device, because thats not allowed. So in short, whats the correct way to manage adding extra disks to the nas after configuring zfs? The new disks wont be going into that pool as it happens, they will probably be in software raid 1 with my current plan. Basically I need to create the zfs pool and copy my old nas data to it, then take the disks out of the old nas and add them to the nas4free box. But thats problematic if each disk increments the ada numbers and they start falling off the end of the array...

If I've missed an obvious how to, point me at it and I'll shut up!

[rostreich]

You build a vdev with physical disks. After creating a vdev it is 'locked'. Means you can't add or remove a single disk from it. (Besides replacing a faulty one or replacing all of them after another for bigger ones (and resilvering!) to grow the vdev and so the pool).

A pool is built from a vdev or more.
The only thing to expand is your pool. And you can only expand a pool by adding another vdev into it. This can be another another mirror vdev or raidz in any form. but mixing mirror vdev and raidz isn't suggested, because the whole pool limits then to read/write speed you'll get out of the raidz-vdev.

my tip for you is:
start from scratch. build 2 mirror vdevs and take that into your pool. enjoy great read speeds, because a pool is a stripe raid from your two vdevs.

[slaycock]

Export your pool. Shutdown. Install a new disk. Restart. Configure new disk. Import Zpool.

[yojimbo]

Hi, I get that, well after reading zfs guide, maybe I wasn't clear or I am misunderstanding.

I have 4 WD disks at ada0,1,2,3, I make a vdev out of them, add them to a pool and I can use it etc. I then add a Hitachi disk, which is registered at ada0, and the WD disks get incremented, the status of the disks is shown as being wrong, as it knows 1 has changed, I can scan and import to my hearts content, the issue is that the vdev has now dropped ada4 that was 3. So by adding a disk at a later date, I drop a disk from the vdev, which I cant seem to add back. Right now its not an issue as it still in sandpit stage, but if adding a disk in 2 weeks time is going to break everything, I'd like to know now

[yojimbo]

Export your pool. Shutdown. Install a new disk. Restart. Configure new disk. Import Zpool.

Right, thanks, once the box has finished its current copying operation, I'll restart it back into the nas and try that!

[rostreich]

Sry, I understand now.

slaycock is right!

[yojimbo]

Thanks for the help so far. Looks like it might be a bug.

The good news:

Code: Select all

nas4free:/mnt# zpool import zfspool1
nas4free:/mnt# zpool list
NAME       SIZE  ALLOC   FREE    CAP  DEDUP  HEALTH  ALTROOT
zfspool1  10.9T  5.29G  10.9T     0%  1.00x  ONLINE  -
nas4free:/mnt# zpool status zfspool1
  pool: zfspool1
 state: ONLINE
  scan: resilvered 7.50K in 0h0m with 0 errors on Wed Feb  6 20:24:33 2013
config:

        NAME        STATE     READ WRITE CKSUM
        zfspool1    ONLINE       0     0     0
          raidz1-0  ONLINE       0     0     0
            ada1    ONLINE       0     0     0
            ada4    ONLINE       0     0     0
            ada3    ONLINE       0     0     0
            ada2    ONLINE       0     0     0

errors: No known data errors

The bad news:



So the GUI is ignoring(?) whats actually in the pool, and in other screens, like the mountpoint one, it ignored the new disk, though I could create the filesystem and mount it ok in a shell, meanwhile, it did think it was allowed to mount/format ada4. Command line stuff is ok for me, but is the management interface needing some kind of kick to make it read right?

[raulfg3]

use Disks|ZFS|Configuration|Synchronize to sync webGUI to CLI

[yojimbo]

thats reset things thanks! I can investigate the behaviour a bit more off the back of that and get to grips with what I can expect it to do when I start adding things in. Thanks a lot for your help folks, it's got me in the right direction

[fsbruva]

This is a perfect example of what can happen. The webgui is an interface, but saves its configuration differently. The key piece is that the ZFS status page has the real data... HUZZAH!