Backup schedule should be spread over the day

I suggest some random + exponential backoff, like in CSMA/CD or CSMA/CA:

http://en.wikipedia.org/wiki/Exponential_backoff

https://bugs.launchpad.net/deja-dup/+bug/479191 is related: feature request for detailed scheduling.

The scheduler could default to random backup, and allow overriding by the user.

Looks like the problem is fairly isolated in common/CommonUtils.vala:

in next_run_date(), it always returns the return of most_recent_scheduled_date(), or if comparing to last_run returns a negative timespan, then it adds the configured period.

Turns out that most_recent_scheduled date always returns a DateTime at 00:00Z due to the way it's computed.

Uploaded to precise. Will subscribe ubuntu-sru. If they like it, I can upload to quantal too.

This bug was fixed in the package deja-dup - 26.0-0ubuntu1

---------------
deja-dup (26.0-0ubuntu1) raring; urgency=low

  * New upstream release
    - Only use the GNOME Shell interface when actually in GNOME Shell,
      not something that is merely similar, like the Cinnamon shell
      (LP: #1155929)
    - When testing a restore, also use a temporary directory that is
      on the same partition as the include files (LP: #1159749)
    - Spread default backup time around a bit, from always starting at
      midnight UTC to starting between 2 and 4 AM local time
      (LP: #1154920)
    - Use more-aggressively-idle modes for ionice and nice if available
 -- Michael Terry <email address hidden> Thu, 28 Mar 2013 13:01:53 -0400

Hello Sidnei, or anyone else affected,

Accepted deja-dup into precise-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/deja-dup/22.0-0ubuntu4 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

Seems to fix the problem as expected.

Tested 22.0-0ubuntu4 on precise by enabling -proposed.

The verification of this Stable Release Update has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regresssions.

This bug was fixed in the package deja-dup - 22.0-0ubuntu4

---------------
deja-dup (22.0-0ubuntu4) precise-proposed; urgency=low

  * debian/patches/spread-backup-epoch.patch:
    - Don't always start backup times from midnight UTC. Rather, start
      between 2-4 AM local time. LP: #1154920
 -- Michael Terry <email address hidden> Thu, 28 Mar 2013 14:01:05 -0400

quantal has seen the end of its life and is no longer receiving any updates. Marking the quantal task for this ticket as "Won't Fix".