Boot, Mirror and Grow

[MtK]

Hey,
now that FN supports ZFS on the boot device, does it also support the same Grow/Expand path as the data pool?

I have a 4Gb thumb drive used for boot, and I bough 2 new 16Gb Cruzer Fit.

if I do this:

• add one as a mirror to the existing
• remove the old thumb
• add the second new thumb as a replacer for the old one.

Would the boot grow into a 16Gb mirror pool?

 

[dlavigne]

An easier approach is to backup the config, install the latest STABLE and select both thumb drives as the install target. After the first reboot, import the pool and upload your config.

 

[Mlovelace]

I just did what @dlavigne suggested above and it is a much faster approach to expanding the boot pool. The resilver time on the usb drives would be painfully slow.

 

[MtK]

I just did what @dlavigne suggested above and it is a much faster approach to expanding the boot pool. The resilver time on the usb drives would be painfully slow.

well, we are talking about 16Gb at most, not 16 Pb...

 

[cyberjock]

Yes, but since USB has horrendously slow random-write performance (often 1MB/sec or less) I agree it's better to just do a fresh install.

Boot pools don't expand either, so that idea isn't an option anyway. ;)

 

[Bidule0hm]

And if we set auto_expand to yes? or there is another catch?

 

[cyberjock]

It doesn't work. There's a ticket discussing that. There's risk of it not being bootable.

 

[Bidule0hm]

Ok, thanks ;)

 

[sef]

To answer the original question: it'll grow after a reboot.

I've done it several times.

Of course, now I've got a 64g freenas-boot pool...

 

[Bidule0hm]

Wait, cyberjock tell me it doesn't work and you tell me it works. Who is right?

 

[sef]

I forget the reason for the case where it didn't work. But it does, at least every time I try it. (Just recognizing it won't work until you reboot.)

Also, there is no harm to setting autoexpand ("zfs set autoexpand=on freenas-boot") yourself; FreeNAS won't do anything about it, either way.

That's assuming you want the behaviour, of course.

 

[Bidule0hm]

Ok, in short it works but there is some edge cases where it doesn't. Thanks ;)

 

[cyberjock]

Hmm... maybe someone (a dev) can reply to the last statement made by DrKK https://bugs.freenas.org/issues/7314


Never got confirmation about the "misbehavior" that DrKK wrote about. Note that I'm not saying that we should reexamine 7314 and turn autoexpand=on. Just saying that there's also unresolved questions that went unanswered. I have other questions now, but I'll take that to emails.

 

[MtK]

Hey,
now that FN supports ZFS on the boot device, does it also support the same Grow/Expand path as the data pool?

I have a 4Gb thumb drive used for boot, and I bough 2 new 16Gb Cruzer Fit.

if I do this:

• add one as a mirror to the existing
• remove the old thumb
• add the second new thumb as a replacer for the old one.

Would the boot grow into a 16Gb mirror pool?

I can confirm it works!
it took 2 (very long!) resilvers... but I now have a mirrored 16Gb boot pool!

 

[AVB]

I can't speak for upgrading to another USB stick but going to a pair of cheap SSD's from a USB stick worked fine for me. Considering how cheap a 20 or 30GB SSD is that would be the route I'd take...and did.

 

[Bidule0hm]

Even one SSD is better than a pair of USB sticks... :)