Balancing MaaS Backup Integrity with Service Uptime

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Hi there,

I am following https://maas.io/docs/how-to-back-up-maas to set up a periodic backup task for maas db and its supported files. The document suggests to stop MaaS services, which should be fine for a clean backup (and restore). Every stop/start activity creates a service disruption. Is it a requirement to stop MaaS services while doing a periodic backup?

Reading through pg_dumpall (the tool used for db backup) documentation:

  • pg_dumpall backs up all database and uses pg_dump underneath to backup a database.
  • pg_dump process requests shared locks ACCESS SHARE (AccessShareLock) on table before doing a dump - this is to prevent some application trying to drop table while a dump is happening.
  • pg_dump does not block other users accessing the database (readers or writers), which means update operations will still happen.
  • The dump begins with setting TRANSACTION ISOLATION LEVEL SERIALIZABLE. Everything after pg_dump sets the transaction isolation level is not part of this dump.

To me this means its safe to perform periodic backup without stopping MaaS services, its just that any insert/update operation that happens in MaaS db during the time pg_dump happens won’t be part of the backup, however they will be backed-up during the next run.

Appreciate thoughts/comments!