
Hello everyone!
We are about to upgrade a 6 instance cluster from pg92 to pg10 using pg_upgrade with hardlinks and rsync.
Our preliminary tests are working really good so far but on question has popped up that we feel is really critical because it has an important impact on our failover plan.
After reading the pg_upgrade documentation multiple times, it seems that after running pg_upgrade on the
primary instance, we can't start it until we run rsync from the
primary to the
standby. I'm understanding this from the following section in the pg_upgrade manual page.
```
You will not be running pg_upgrade on the standby servers, but rather rsync on the
primary. Do not start any servers yet.
```
I'm understanding the `any` as
primary and
standbys.
On the other hand, we've been doing tests that start the
primary instance as soon as pg_upgrade is done. This tests have worked perfectly fine so far. We make the rsync call with the
primary instance running and the
standby can start later on after rsync is done and we copy the new configuration files.
If what we are doing is wrong, we need to run `rsync` before starting the primary instance, that would mean that the primary and the
standby are not usable if pg10 doesn't start correctly in the primary right ?
I hope my question is clear enough!
Best,