[lustre-discuss] zpool features, recordsize, post-upgrade?

[Marion Hakanson]

Greetings,

We're upgrading our Lustre servers from CentOS-6 with IEEL-2.3, to
CentOS-7.5 with Lustre community release 2.10.5.  The OSTs are all
on the ZFS backend, originally built on ZoL-0.6.5.

The new 2.10.5 servers come with ZoL-0.7.9, which of course has some
new zpool features available.

Once we've upgraded, should we enable one or more of the new features
in our existing OST zpools?  E.g. large_blocks?  And then update the
ZFS recordsize to whatever a newly-created Lustre 2.10.5 OST would use?

I do realize the new recordize setting wouldn't affect existing files,
but we're also looking at enabling PFL and doing a global "lfs migrate"
operation to re-layout everything for better performance.

Thoughts?  Anyone else been down this road?

Thanks and regards,

Marion