Adding New Drives to a Zpool

[Kenfolk]

I've been doing some research, but haven't found an exact answer, so was hoping to get some help. I'm running Freenas 11.1, 144GB ECC Ram. I have one IBM M1015 flashed, just ordered a second one that I hope to get by the end of this week to flash. Currently have a 24 bay server chasis, and 8 6TB drives in RaidZ2. I've recently purchased 6 8TB drives that I plan on putting in RaidZ2 and would like to add to my existing zpool in a new vdev. After I finish all my burn in testing, what steps do I need to take to add the new drives into a RaidZ2 configuration, and from there how do I add it to the pool safely?

As a side question, would there be a way to transfer data from one vdev to the next? I only ask because I'm over 90% capacity on the one vdev (which prompted the expansion) and so I'd like to move some files around to get myself back to 80%.

 

[kdragon75]

Due to the fact that you are over 50% you would need to move the data off the pool, add your new disks, and move your data back.

 

[kdragon75]

Just noticed you will have a mix of sizes in your pool. This can cause slightly unexpected performance. It won't thank your performance but it may not be exactly as you expect as ZFS will favor the new drives in order to keep everything balanced.

 

[danb35]

Due to the fact that you are over 50% you would need to move the data off the pool, add your new disks, and move your data back.

Nonsense. OP can simply add the second RAIDZ2 as a new vdev to his existing pool, as he asked--there's no need at all to manually shift data around. It isn't ideal to have mismatched drive sizes in a pool (or even in a vdev), though it's certainly possible (see my configuration, for example). It also isn't ideal to have mismatched vdevs, though once again it's entirely possible.

what steps do I need to take to add the new drives into a RaidZ2 configuration, and from there how do I add it to the pool safely?

You'd do it all in one step--Storage -> Volume Manager, select your existing pool under Volume to expand, select all your new disks, select RAIDZ2, Extend Volume. Done. Unless the volume manager complains that the number of disks in the new vdev doesn't match the number of disks in the existing vdev, in which case you'd need to use the Manual Setup button instead.

As a side question, would there be a way to transfer data from one vdev to the next?

Not directly, but there's also no real need to. The 80% rule applies to pools, not to vdevs.

 

[Kenfolk]

I was hoping keeping the storage at the same level on both vdevs would be ok, didn't think that having different sized drives (or different number) would be that much of an issue as long as the Raid level and the total storage of both vdevs was the same. Can I expect any major problems having a vdev with 6tb drives and another with 8tb on the same pool?

Doing it all in that one step seems simple enough, I was worried it would be similar to when I set it up to begin with

I'm glad that 80% rule applies only to pools, effectively doubling my storage should then bring that 90% down to 45%

 

[danb35]

Can I expect any major problems having a vdev with 6tb drives and another with 8tb on the same pool?

I wouldn't expect so--there's probably a bit of a performance hit, but you wouldn't be using RAIDZ2 for max performance in any case. I've been running the configuration in my sig for about two years now without issues (at least, without issues attributable to the pool configuration).

 

[Kenfolk]

No, performance isn't a major need, it mainly houses my media files that I access via my computer. As long as performance doesn't suffer enough I can no longer play my media over the network I'll be golden

 

[Ericloewe]

If you really want to, replicate some of your stuff to a new dataset and it will be balanced among the available space.

 

[Kenfolk]

Thanks for all the help, I was able to mount the drives successfully. I forgot to do my burn in tests before I mounted so I won't be able to do a badblocks test, but I'm running all the smart tests now