You should take a snapshot before starting the upgrade process. You
cannot achieve a snapshot of "the most current situation" in a live
cluster anyway, as data are constantly written to the cluster even after
a node is stopped for upgrading. So you've gotta to accept the outdated
snapshots if you ever want to downgrade.
On the documentation side, I totally agree with you. The Apache
Cassandra documentation on some common tasks, such as upgrading the
cluster, is very lacking. I really hope this can be improved.
On 04/11/2022 08:13, Marc Hoppins wrote:
Hi all,
On a test setup I a looking to do an upgrade from 4.0.3 to 4.0.6.
Would one typically snapshot before DRAIN or after?
If DRAIN after snapshot, I would have to restart the service to
snapshot and would this not then be accepting new operations/data?
If DRAIN before snapshot, would there be the possibility of not having
the most current situation? I realise that the latter option would
render any changes fairly negligible even in a live environment.
Apologies if these questions seem redundant. Apache documentation is
not as comprehensive as it seems to be for (EG) HBASE.
Thanks
M
