
#include "bacula_template.inc" title="Backup Strategies" num=13

<h1>Backup Strategies</h1>
Although Recycling and Backing Up to Disk Volume have been
discussed in previous chapters, this chapter is meant to give
you an overall view of possible backup strategies and to  
explain their advantages and disadvantages.

<a name="Simple"></a>
<h2>Simple One Tape Backup</h2>
Probably the simplest strategy is to back everything up to a 
single tape and inserting a new (or recycled) tape when the
tape fills and Bacula requests a new tape.
<h3>Advantages</h3>
<ul>
  <li>The operator intervenes only when a tape change is needed.
      (once a month at my site).</li>
  <li>There is little chance of operator error because the tape
      is not changed daily.</li>
  <li>A minimum number of tapes will be needed for a full restore.
      Typically the best case will be one tape and worst two.</li>
  <li>You can easily arrange for the Full backup to occur a different
      night of the month for each system, thus load balancing and 
      shortening the backup time.</li>
</ul>
<h3>Disadvantages</h3>
<ul>   
  <li>If your site burns down, you will lose your current backups,     
      and in my case about a month of data.</li>
  <li>After a tape fills and you have put in a blank tape, the
      backup will continue, and this will generally happen during
      working hours.</li>
</ul>
<h3>Practical Details</h3>
This system is very simple. When the tape fills and Bacula requests
a new tape, you <b>unmount</b> the tape from the Console program,
insert a new tape and <b>label</b> it. In most cases after the
label, Bacula will automatically mount the tape and resume the
backup. Otherwise, you simply <b>mount</b> the tape.   
<p>
Using this strategy, one typically does a Full backup once a
week following by daily Incremental backups. To minimize the
amount of data written to the tape, once can do (as I do)
a Full backup once a month on the first Sunday of the month,
a Differential backup on the 2nd-5th Sunday of the month,
and incremental backups the rest of the week.  

<a name="Manual"></a>
<h2>Manually Changing Tapes</h2>
If you use the strategy presented above, Bacula will ask
you to change the tape, and you will <b>unmount</b> it and
the remount it when you have inserted the new tape.
<p>
If you do not wish to interact with Bacula to change each
tape, there are several ways to get Bacula to release the tape:
<ul>
  <li>In your Storage daemon's Device resource, set<br>
      <b>AlwaysOpen = no</b><br>
      In this case, Bacula will release the tape after
      every job. If you run several jobs, the tape will be
      rewound and repositioned to the end at the beginning
      of every job. This is not very efficient, but does let
      you change the tape whenever you want.
      </li>

  <li>Use a <b>RunAfterJob</b> statement to run a script after
      your last job.  This could also be an <b>Admin</b>
      job that runs after all your backup jobs.  The script could be
      something like:

      <pre>
      \#!/bin/sh
      /full-path/console -c /full-path/console.conf &lt;&lt;END_OF_DATA
      release storage=your-storage-name
      END_OF_DATA
      </pre>

      In this example, you would have <b>AlwaysOpen=yes</b>,
      but the <b>release</b> command would tell Bacula to
      rewind the tape and on the next job assume the tape
      has changed.  This strategy may not work on some systems,
      or on autochangers because Bacula will still keep the
      drive open.</li> 

  <li>The final strategy is the similar to the previous 
      case except that you would use the unmount command
      to force Bacula to release the drive. Then you would
      eject the tape, and remount it as follows:
      <pre>
      \#!/bin/sh
      /full-path/console -c /full-path/console.conf &lt;&ltEND_OF_DATA
      unmount storage=your-storage-name
      END_OF_DATA
      \# the following is a shell command
      mt eject
      /full-path/console -c /full-path/console.conf &lt;&lt;END_OF_DATA
      mount storage=your-storage-name
      END_OF_DATA
      </pre>
      </li>
</ul>

<a name="Daily"></a>
<h2>Daily Tape Rotation</h2>
This scheme is quite different from the one mentioned above in
that a Full backup is done to a different tape every day of
the week.  Generally, the backup will cycle continuously
through 5 or 6 tapes each week.  Variations are to use
a different tape each Friday, and possibly at the beginning
of the month.  Thus if backups are done Monday through Friday
only, you need only 5 tapes, and by having two Friday tapes,
you need a total of 6 tapes. Many sites run this way, or
using modifications of it based on two week cycles or longer.
<h3>Advantages</h3>
<ul>
  <li>All the data is stored on a single tape, so recoveries
      are simple and faster.</li>
  <li>Assuming the previous day's tape is taken offsite each
      day, a maximum of one days data will be lost if the
      site burns down.</li>
</ul>
 
<h3>Disadvantages</h3> 
<ul>
  <li>The tape must be changed every day requiring a lot of
      operator intervention.</li>
  <li>More errors will occur because of human mistakes.</li>
  <li>If the wrong tape is inadvertently mounted, the Backup for
      that day will not occur exposing the system to data loss.</li>
  <li>There is much more movement of the tape each day (rewinds)
      leading to shorter tape drive life time.</li>
  <li>Initial setup of Bacula to run in this mode is more complicated
      than the Single tape system described above.</li>
  <li>Depending on the number of systems you have and their data
      capacity, it may not be possible to do a Full backup every
      night for time reasons or reasons of tape capacity.</li>
</ul>

<h3>Practical Details</h3>
The simplest way to &quot;force&quot; Bacula to use a different
tape each day is to define a different Pool for each day of the
the week a backup is done.  In addition, you will need to specify
appropriate Job and File retention periods so that Bacula will
relabel and overwrite the tape each week rather than appending
to it.  Nic Bellamy has supplied an actual working model of this
which we include here. 
<p>What is important is to create a different Pool for each day
of the week, and on the <b>run</b> statement in the Schedule, to
specify which Pool is to be used.  He has one Schedule that
accomplishes this, and a second Schedule that does the same
thing for the Catalog backup run each day after the main
backup (Priorities were not available when this script was 
written).  In addition, he uses a <b>Max Start Delay</b> of 
22 hours so that if the wrong tape is premounted by the
operator, the job will be automatically canceled, and
the backup cycle will re-synchronize the next day.
He has named his Friday Pool <b>WeeklyPool</b> because
in that Pool, he wishes to have several tapes to be able
to restore to a time older than one week.
<p>And finally, in his Storage daemon's Device resource,
he has <b>Automatic Mount = yes</b> and 
<b>Always Open = No</b>. This is necessary for the tape
ejection to work in his <b>end_of_backup.sh</b> script
below.
<p>
For example, his bacula-dir.conf file
looks like the following:
<pre> 
\# /etc/bacula/bacula-dir.conf
\#
\# Bacula Director Configuration file
\#

Director {
  Name = ServerName
  DIRport = 9101
  QueryFile = "/etc/bacula/query.sql"
  WorkingDirectory = "/var/lib/bacula"
  PidDirectory = "/var/run"
  SubSysDirectory = "/var/lock/subsys"
  Maximum Concurrent Jobs = 1
  Password = "console-pass"
  Messages = Standard
}

\#
\# Define the main nightly save backup job
\#
Job {
  Name = "NightlySave"
  Type = Backup
  Client = ServerName 
  FileSet = "Full Set"
  Schedule = "WeeklyCycle"
  Storage = Tape
  Messages = Standard
  Pool = Default
  Write Bootstrap = "/var/lib/bacula/NightlySave.bsr"
  Max Start Delay = 22h
}

\# Backup the catalog database (after the nightly save)
Job {
  Name = "BackupCatalog"
  Type = Backup
  Client = ServerName 
  FileSet = "Catalog"
  Schedule = "WeeklyCycleAfterBackup"
  Storage = Tape
  Messages = Standard
  Pool = Default
 \# This creates an ASCII copy of the catalog
  RunBeforeJob = "/usr/lib/bacula/make_catalog_backup -u bacula"
 \# This deletes the copy of the catalog, and ejects the tape
  RunAfterJob  = "/etc/bacula/end_of_backup.sh"
  Write Bootstrap = "/var/lib/bacula/BackupCatalog.bsr"
  Max Start Delay = 22h
}

\# Standard Restore template, changed by Console program
Job {
  Name = "RestoreFiles"
  Type = Restore
  Client = ServerName 
  FileSet = "Full Set"
  Storage = Tape
  Messages = Standard
  Pool = Default
  Where = /tmp/bacula-restores
}


\# List of files to be backed up
FileSet {
  Name = "Full Set"
  Include = signature=MD5 { 
    /
    /data
  }
  Exclude = { /proc /tmp /.journal }
}

\#
\# When to do the backups
\#
Schedule {
  Name = "WeeklyCycle"
  Run = Level=Full Pool=MondayPool Monday at 8:00pm
  Run = Level=Full Pool=TuesdayPool Tuesday at 8:00pm
  Run = Level=Full Pool=WednesdayPool Wednesday at 8:00pm
  Run = Level=Full Pool=ThursdayPool Thursday at 8:00pm
  Run = Level=Full Pool=WeeklyPool Friday at 8:00pm
}

\# This does the catalog. It starts after the WeeklyCycle
Schedule {
  Name = "WeeklyCycleAfterBackup"
  Run = Level=Full Pool=MondayPool Monday at 8:15pm
  Run = Level=Full Pool=TuesdayPool Tuesday at 8:15pm
  Run = Level=Full Pool=WednesdayPool Wednesday at 8:15pm
  Run = Level=Full Pool=ThursdayPool Thursday at 8:15pm
  Run = Level=Full Pool=WeeklyPool Friday at 8:15pm
}

\# This is the backup of the catalog
FileSet {
  Name = "Catalog"
  Include = signature=MD5 {
     /var/lib/bacula/bacula.sql
  }
}

\# Client (File Services) to backup
Client {
  Name = ServerName
  Address = dionysus
  FDPort = 9102
  Catalog = MyCatalog
  Password = "client-pass"
  File Retention = 30d
  Job Retention = 30d
  AutoPrune = yes
}

\# Definition of file storage device
Storage {
  Name = Tape
  Address = dionysus
  SDPort = 9103
  Password = "storage-pass"
  Device = Tandberg
  Media Type = MLR1
}

\# Generic catalog service
Catalog {
  Name = MyCatalog
  dbname = bacula; user = bacula; password = ""
}

\# Reasonable message delivery -- send almost all to email address
\#  and to the console
Messages {
  Name = Standard
  mailcommand = "/usr/sbin/smtp -h localhost -f \"\(Bacula\) %r\" 
     -s \"Bacula: %t %e of %c %l\" %r"
  operatorcommand = "/usr/sbin/smtp -h localhost -f \"\(Bacula\) %r\"
     -s \"Bacula: Intervention needed for %j\" %r"
  mail = root@localhost = all, !skipped            
  operator = root@localhost = mount
  console = all, !skipped, !saved
  append = "/var/lib/bacula/log" = all, !skipped
}
    
\# Pool definitions
\#
\# Default Pool for jobs, but will hold no actual volumes
Pool {
  Name = Default
  Pool Type = Backup
}

Pool {
  Name = MondayPool
  Pool Type = Backup
  Recycle = yes
  AutoPrune = yes
  Volume Retention = 6d
  Accept Any Volume = yes
  Maximum Volume Jobs = 2
}

Pool {
  Name = TuesdayPool
  Pool Type = Backup
  Recycle = yes
  AutoPrune = yes
  Volume Retention = 6d
  Accept Any Volume = yes
  Maximum Volume Jobs = 2
}

Pool {
  Name = WednesdayPool
  Pool Type = Backup
  Recycle = yes
  AutoPrune = yes
  Volume Retention = 6d
  Accept Any Volume = yes
  Maximum Volume Jobs = 2
}

Pool {
  Name = ThursdayPool
  Pool Type = Backup
  Recycle = yes
  AutoPrune = yes
  Volume Retention = 6d
  Accept Any Volume = yes
  Maximum Volume Jobs = 2
}

Pool {
  Name = WeeklyPool
  Pool Type = Backup
  Recycle = yes
  AutoPrune = yes
  Volume Retention = 12d
  Accept Any Volume = yes
  Maximum Volume Jobs = 2
}

\# EOF
</pre>
Note, the mailcommand and operatorcommand should be on a single line
each. They were split to preserve the proper page width. 

In order to get Bacula to release the tape after the nightly backup,
he uses a <b>RunAfterJob</b> script that deletes the ASCII copy of
the database back and then rewinds and ejects the tape.  The
following is a copy of <b>end_of_backup.sh</b>
<pre>
\#! /bin/sh

/usr/lib/bacula/delete_catalog_backup

mt rewind
mt eject

exit 0
</pre>

Finally, if you list his Volumes, you get something like the following:
<pre>
<font size=-2>
*list media
Using default Catalog name=MyCatalog DB=bacula
Pool: WeeklyPool
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
| MeId| VolumeName| MedTyp| VolStat| VolBytes  | LastWritten     | VolRet| Recyc|
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
| 5   | Friday_1  | MLR1  | Used   | 2157171998| 2003-07-11 20:20| 103680| 1    |
| 6   | Friday_2  | MLR1  | Append | 0         | 0               | 103680| 1    |
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
Pool: MondayPool
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
| MeId| VolumeName| MedTyp| VolStat| VolBytes  | LastWritten     | VolRet| Recyc|
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
| 2   | Monday    | MLR1  | Used   | 2260942092| 2003-07-14 20:20| 518400| 1    |
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
Pool: TuesdayPool
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
| MeId| VolumeName| MedTyp| VolStat| VolBytes  | LastWritten     | VolRet| Recyc|
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
| 3   | Tuesday   | MLR1  | Used   | 2268180300| 2003-07-15 20:20| 518400| 1    |
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
Pool: WednesdayPool
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
| MeId| VolumeName| MedTyp| VolStat| VolBytes  | LastWritten     | VolRet| Recyc|
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
| 4   | Wednesday | MLR1  | Used   | 2138871127| 2003-07-09 20:2 | 518400| 1    |
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
Pool: ThursdayPool
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
| MeId| VolumeName| MedTyp| VolStat| VolBytes  | LastWritten     | VolRet| Recyc|
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
| 1   | Thursday  | MLR1  | Used   | 2146276461| 2003-07-10 20:50| 518400| 1    |
+-----+-----------+-------+--------+-----------+-----------------+-------+------+
Pool: Default
No results to list.
</font>
</pre>

Note, I have truncated a number of the columns so that the information fits
on the width of a page.
 
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