Comment 26 for bug 1852502

Hi folks, an important piece of information I forgot to past long ago when I hit this problem.
I was able to get rid of the errors by manually upgrading mongo from 3.6 to 4. This was a manual upgrade, and not recommended, but IFIK, juju 3 will bring mongo 4 so, the problem should be fixed there.

The tests I did was, first I setup an environment to reproduce the problem and measure the rate it was recurring. I used 4 vCPU 8GB VMs juju HA controller and had FIO running in the 3 controllers while I continuously took backups with mongodump. With mongo 3.6 I got the following failure rate:

Runs Failures
20 3
40 5
64 7
139 19

After I upgraded mongo to 4.X, there was not failures anymore even after 300 iterations and backups.
are faster as well.