I am currently running TrueNAS Core 13.0-U6.1 as a media server and also as a file server to back up other systems in the house. As part of my overall backup strategy, I use an external USB drive (single disk) to create a backup copy of my TrueNAS data that can be taken to a remote location.
The USB drive was originally set up in 2021 and formatted with ZFS. When I attach the USB drive and import the volume, I get a message about running an old version of ZFS on that drive. Does it matter that I’m running a three year old version of ZFS?
I use rsync for the backup as follows (the data is on data1 and the target is usb-backup3): rsync -avh --stats --delete /mnt/data1/ /mnt/usb-backup3/
The old version of ZFS simply means that the pool on your USB drive can’t use newer features available in the current TrueNAS Core 13.0-U6.1 software.
OpenZFS is under constant development and improvement. Things like new checksums, compression and internal features have been added.
We tend to not recommend updating ZFS pools, except when you have a specific need. Or have a clear understanding of what software can read the pool. If you upgrade a pool, only that version of ZFS or later can read & write the pool.
You can get the feature’s list of your USB pool by using this zpool get all usb-backup3 | egrep -i "name|feature"
“active” ones are in use
“enabled” ones are not currently used, but could be
“disabled” are not available in that pool, (yet)
There is a complicated method to figure out what features are old enough to enable. And have plenty versions of TrueNAS or ZFS on Linux that the pool can still be usable. However, I won’t go into it because I can’t describe it well.
