I'm running 7.3.0-rc.1, and have an unusual question. Is it possible to shrink the size of the internal boot pool? Right now, I have a 256GB and a 512GB SSD in use and am thinking of getting a pair of 16GB Optane SSDs to use for booting. Is there a procedure for this?

ZFS cannot be shrunk; you could use the flash drive to boot again. Just first copy the contents of the boot pool /config folder to the flash, then boot from the flash and recreate the internal boot pool with the new devices.

Note that if you are using a split pool, you would also need to back up the data partition.

I wish the boot pool dialog gave you the option to split pool. So I can boot from the SSD and still have the remaining space for cache. Currently the dialog just uses the entire disk space (500gb ssd) as the boot.

1 hour ago, vac59 said:

I wish the boot pool dialog gave you the option to split pool. So I can boot from the SSD and still have the remaining space for cache. Currently the dialog just uses the entire disk space (500gb ssd) as the boot.

I went back and re-did the setup. I see the boot + data option 😓 My last gripe is that the boot file system chosen is ZFS ehh i guess that's the new fad. But with memory costs and constraints i would rather skip the memory use.

There is no other option being offered for the internal boot partition, but the RAM overhead for such a small partition will be negligible. The data partition can be any supported format.

14 hours ago, vac59 said:

But with memory costs and constraints i would rather skip the memory use.

Memory is only used if there's nothing else needing it.

15 hours ago, vac59 said:

My last gripe is that the boot file system chosen is ZFS ehh i guess that's the new fad. But with memory costs and constraints i would rather skip the memory use.

ZFS caches reads in memory, the OS is loaded once, ZFS will not use the RAM for ARC after that or very minimally <1GB

Here is my backup NAS running only btrfs disks with a boot pool, ZFS is using 329MiB of RAM, thats it.