juju create-backup: Failed: oplog overflow: mongodump was unable to capture all new oplog entries during execution;

[Felipe Reyes]

when running juju create-backup in a fairly big database the following error was raised:

Failed: oplog overflow: mongodump was unable to capture all new oplog entries during execution;

This happens when mongodump is being generated from a SECONDARY replica set, more details at https://jira.mongodb.org/browse/SERVER-26210

So juju should always connect to the PRIMARY when generating a mongodump.

[Paul Collins (pjdc)]

I ran into this consistently on a JAAS controller we were preparing to upgrade to 2.4.7, apparently always while backing up statueshistory. So perhaps it's also a function of busyness as well as or instead of size?

[Felipe Reyes (freyes)]

On Tue, 2018-12-04 at 01:21 +0000, Paul Collins wrote:
> I ran into this consistently on a JAAS controller we were preparing
> to
> upgrade to 2.4.7, apparently always while backing up
> statueshistory. So
> perhaps it's also a function of busyness as well as or instead of
> size?

A more busy db will lead to drop ops from the oplog sooner, so yes, if
environment's IO is not fast enough and jujud is doing too many writes
is when you may need to tune this parameter.

[Felipe Reyes (freyes)]

tune it, or get the backup from the PRIMARY as it was agreed.

[Anastasia (anastasia-macmood)]

Removing from a milestone as this work will not be done in 2.5 series.

[Canonical Juju QA Bot (juju-qa-bot)]

This bug has not been updated in 2 years, so we're marking it Low importance. If you believe this is incorrect, please update the importance.