to "zpool upgrade" or not to "zpool upgrade"?

[HRS]

I recently saw a message that certain features are missing on my pool and that I should upgrade, the message warned that some apps might fail and that the operation is not reversible.
Naturally, in light of the warning I'm hesitant to perform the upgrade
I saw several posts on this issue (post1, post2, post3) but none had conclusive advice

So, as I paraphrased Hamlet in the title of this post - should I upgrade?

I'm currently running the latest version of Truenas Scale - Bluefin, but the pool has not been upgraded in many (many) years

I know that "if it ain't broke - don't fix it", but I guess I'll have to upgrade sometime....

 

[Ericloewe]

See https://www.truenas.com/community/resources/zfs-feature-flags-in-truenas.95/

 

[HRS]

thanks @Ericloewe
according to the feature list in the link you've sent my pool supports the features up to "TrueNAS 12.0". The "TrueNAS 12.0" features are all disabled

I have no idea if any of my apps either require these features of would fail if they are enabled
What's your recommendation?

 

[Ericloewe]

Well, apps can't require them because they're not remotely aware of them. Whether they can benefit is a more nuanced question:
There are a few nice-to-haves in the mix, which can result in tangible improvements. Log spacemap is probably the most interesting one. Zstd is also interesting if you need lots of compression but feel that gzip is too slow.

So, nothing revolutionary, but lots of targeted improvements. Worth the upgrade?
Do you need to replicate to older systems? Do you need to open the pool in older systems? Do you feel the need to roll back to an older version?

If you answered no to all three questions, go ahead and upgrade.

 

[HRS]

Thanks.
Following your checklist, I went ahead and upgraded the pool. It only took a second. thanks again