Ubuntu ZFS bpool size

Preventing bpool space issues with Ubuntu running on ZFS.

I <3 ZFS

And Ubuntu 20.4 finally made it easy to install Ubuntu with ZFS and the automated snapshots make it easy to roll back should an error occur.

...but... after extended use you might see an issue - snapshots stop being taken when you install new packages. Or at all. Whch means if there's an issue your latest backup could be from months ago, yikes. So what gives?

Well, the default bpool size is 2048MB or less. And after a few kernel updates... you can no longer make snapshots of bpool which prevents ANY autosys_xxx snapshot from running.  

I'm not sure if there's any way to update the bpool size in a live system (if there is please let me know at tips@devstderr.com).

HOWEVER you can increase the size of bpool during install. So I'll assume you're doing a fresh install.  (Warning this will obviously wipe your entire computer, so make sure oyu want to do this.)

1) After booting into a live Ubuntu USB hit "try now."

2) Open the terminal and and run

sudo nano /usr/share/ubiquity/zsys-setup

3) find the line with [ ${bpool_size}-gt 2048 ] && bpool_size=2048 and change the line to bpool_size=10480 to increas the size by a factor of 5.

4) Save and close nano

5) Complete the Ubuntu install with ZFS (you'll have to check experimental.)

Bonus: Want encryption on root with ZFS?  https://linsomniac.gitlab.io/post/2020-04-09-ubuntu-2004-encrypted-zfs/