Is extending RAIDZ volumes coming soon?

[joeinbend]

Hey all, I read that ZFS has added the ability to extend/grow volumes in recent months. Is the ability to grow a RAIDZ volume in FreeNAS on the road map? I would love to be able to grow my current three disk RAIDZ to four, by just adding an additional disk of the same size. Just curious if this is coming soon, or if I've misunderstood and this is still technical limitation in ZFS.

Thanks for everything you guys do, I've been a FreeNAS fanatic for many years!

 

[Ericloewe]

It's coming, but it's going to be about a year before it actually shows up, plus who-knows-how-long to debug it.

 

[Arwen]

Yes, at least a year.

And when it does show up, it will months more, maybe another year before it's on FreeNAS. (Which is a good thing. Let everyone else experience the problems, and get them fixed, before masses of people think it's ready for them.)

 

[nightshade00013]

Yep, the announcement from the ZFS foundation is that they are working on it.... Like they had the concept done when it was announced. They still have to do the work to make it happen and then test it before release. I would be surprised if it came out before 2020 to be honest.

If you are wanting to grow your pool you can always get a few drives and either add a second vDev or create a second pool. For right now that is your best option especially if your pool is getting full and it won't last more than a year.

 

[joeinbend]

Thanks for the replies everyone. The piece I had misunderstood was the announcement from OpenZFS about this feature, I had incorrectly interpreted that as a release announcement, rather than "we're working on it!". @nightshade00013 that's exactly the wall I'm up against: I need to grow my pool, and even though I've been a FN user for many many years, I somehow overlooked that I couldn't just add a disk to a RAIDZ and grow. Oops! Thanks again for all the hard work on this project; I've enjoyed seeing FN grow and mature over the years. I also really like the new webUI, it looks like it's getting close (if not already) feature parity with the legacy UI. Love it!

 

[joeinbend]

Slightly off topic, but I guess there's no harm in hijacking my own thread :) At this time I'm working thru my storage upgrade path (thus the original title of my thread here). I tested this out in a VM to make sure it would work: If one has an existing RAIDZ volume, it seems the only viable in-place upgrade is to add at least 3 more disks (not necessarily the same size as the existing RAIDZ disks, nor the same number of disks), then one can extend the existing RAIDZ, effectively striping across the two.

This seems to me also, to be the most efficient use of overall disk space. With two striped RAIDZ's which are "only" giving up one disks' capacity each (2 overall), that's still more efficient than striped mirrors, where you're giving up 50% of every pair.

My question, is this kosher? any reason not to stripe across RAIDZ's?

 

[Ericloewe]

any reason not to stripe across RAIDZ's?

Not really, no.

 

[Nick2253]

any reason not to stripe across RAIDZ's?

The obvious reason not to do this is the same reason why you wouldn't want to stripe in the first place: if any one stripe vdev dies, it takes the whole pool with it. That being said, the increased risk is relatively minor in my opinion, and you will get a I/O performance boost with a stripe (though you may not realize it if you only connect via 1GBps, and with only a few clients at a time).

 

[kdragon75]

Could you not also replace each disk and resilver until all disks are replaced with larger ones? Perhaps slightly risky though.

 

[Ericloewe]

Could you not also replace each disk and resilver until all disks are replaced with larger ones? Perhaps slightly risky though.

It's effectively risk-free (at least compared to normal operation) if you have a spare port. You can replace a disk that is still in place and it will only be removed after the new one is resilvered.

 

[kdragon75]

It's effectively risk-free (at least compared to normal operation) if you have a spare port. You can replace a disk that is still in place and it will only be removed after the new one is resilvered.

That's a handy trick! Thanks for sharing.

 

[Stux]

What is your current disk layout?

 

[diskdiddler]

It's effectively risk-free (at least compared to normal operation) if you have a spare port. You can replace a disk that is still in place and it will only be removed after the new one is resilvered.

Unfortunately I'll probably do this in the next year, I'm scared. Replacing 6x5's with I think 6x8's or 6x10's. I expect it to take nearly 2 weeks,...

 

[Ericloewe]

You might get it over with more quickly than that with the improvements to scrub/resilver.

 

[diskdiddler]

You might get it over with more quickly than that with the improvements to scrub/resilver.

I'm at 27 hour scrubs now.... With latest version! My poor little server, needs 4k spent on it

 

[kdragon75]

I don't scrub my pool right now but thats probably because the drives are in a pile on the floor waiting for a new motherboard. ;)