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 .. code-block:: bash
  12
  13   TARGET='s3+http://<my-bucket-name>'
  14
  15 Also on the AWS side, I set up a lifecycle rule to archive the backups to Glacier after 7 days.
  16
  17 I did run into some issues getting the backups to work together with `powernap`_, which was configured to put the system to sleep after a few minutes of inactivity.
  18
  19 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. Second, the backups were scheduled for the middle of the night when the system would normally already be asleep.
  20
  21 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.
  22
  23 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...)
  24
  25 The first night I ran the backup, I had to prime the /sys/class/rtc/rtc0/wakalarm time manually, but since then the script has
  26 set the wakeup time for the next day
  27
  28 The final /usr/local/bin/duply-nightly script is below
  29
  30 .. code-block:: bash
  31
  32   #!/bin/sh +x
  33
  34   /usr/bin/logger "Running nightly backup from $0"
  35
  36   # Disable powernap during the backup
  37   service powernap stop
  38
  39   /usr/bin/duply nightly backup
  40
  41   # Wakeup the system at 3:00am tomorrow
  42   echo 0 > /sys/class/rtc/rtc0/wakealarm
  43   echo `date '+%s' -d '3am next day'` > /sys/class/rtc/rtc0/wakealarm
  44
  45   # Enable powernap again.
  46   service powernap start
  47
  48 The cron job that kicks on /usr/local/bin/duply-nightly is below
  49
  50 .. code-block:: bash
  51
  52   SHELL=/bin/sh
  53   PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
  54
  55   5 3 * * * root env HOME=<myhomedir> /usr/local/bin/duply-nightly > /var/log/duply-nightly.log
  56
  57 .. _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/
  58 .. _powernap: https://launchpad.net/powernap
  59 .. _an RTC wakeup: http://www.linux.com/learn/docs/672849-wake-up-linux-with-an-rtc-alarm-clock