content/hints/duply-with-powernap.rst

   1 Duply with a powernapping system
   2 #################################
   3
   4 :date: 2015-02-17
   5 :tags: hints,ubuntu,duply,powernap
   6 :category: hints
   7 :author: Jude N
   8
   9 I've started `backing up one of my systems to S3`_.  The instructions from the Phusion blog worked almost perfectly, except my TARGET line was::
  10
  11   TARGET='s3+http://<my-bucket-name>
  12
  13 Also on the AWS side, I set up a lifecycle rule to archive the backups to Glacier after 7 days.
  14
  15 I did run into some issues getting the backups to work together with `powernap`_, which is configured to put the system to sleep after a few minutes of keyboard inactivity.
  16
  17 Powernap was causing a problem on two fronts.  First, the system was going to sleep mid-backup since full backups take longer than the powernap inactivity timeout. The other problem was the backup was scheduled for the middle of the night when the system would normally already be asleep.
  18
  19 To get around the mid-backup sleep issue, I made a /usr/local/bin/duply-nightly script which shuts down powernap before calling duply and restarted it afterwards.
  20
  21 In order to get around the system-already-asleep issue, I'm using `an RTC wakeup`_, in /usr/local/bin/duply-nightly to set the system to wake a few minutes before the cron job kicks off (but not early enough for powernap to put the system to bed again...)
  22
  23 The final /usr/local/bin/duply-nightly script is below
  24
  25 .. code-block:: bash
  26
  27   #!/bin/sh +x
  28
  29   /usr/bin/logger "Running nightly backup from $0
  30
  31   # Disable powernap during the backup
  32   service powernap stop
  33
  34   /usr/bin/duply nightly backup
  35
  36   # Wakeup the system at 3:00am tomorrow
  37   echo 0 > /sys/class/rtc/rtc0/wakealarm
  38   echo `date '+%s' -d '3am next day'` > /sys/class/rtc/rtc0/wakealarm
  39
  40   # Enable powernap again.
  41   service powernap start
  42
  43 The cron job that kicks on /usr/local/bin/duply-nightly is below
  44
  45 .. code-block:: bash
  46
  47   SHELL=/bin/sh
  48   PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
  49
  50   5 3 * * * root env HOME=<myhomedir> /usr/local/bin/duply-nightly > /var/log/duply-nightly.log
  51
  52 .. _backing up one of my systems to S3: http://blog.phusion.nl/2013/11/11/duplicity-s3-easy-cheap-encrypted-automated-full-disk-backups-for-your-servers/
  53 .. _powernap: https://launchpad.net/powernap
  54 .. _an RTC wakeup: http://www.linux.com/learn/docs/672849-wake-up-linux-with-an-rtc-alarm-clock