\index[general]{Migration}
\addcontentsline{toc}{section}{Migration}
-The term Migration as used in the context of Bacula means moving data from
-one Volume to another, and in particular it is a Job (similar to a backup
+The term Migration, as used in the context of Bacula, means moving data from
+one Volume to another. In particular it refers to a Job (similar to a backup
job) that reads data that was previously backed up to a Volume and writes
-it to another Volume purging the catalog records associated with the first
-backup job. In other words, Migration moves Bacula Job data from one
+it to another Volume. As part of this process, catalog records associated with the first
+backup job are purged. In other words, Migration moves Bacula Job data from one
Volume to another. Although we mention Volumes to simplify the subject,
-in reality, Migration is based on moving individual Jobs from one Pool to another.
+in reality, Migration is based upon the concept of moving individual Jobs from one Pool to another.
Migrations can be based on quite a number of different criteria such as:
-a single previous Job; a Volume; a Client; a regular expression matching
-a Job, Volume, or Client name; the time a Job is on a Volume; high
-and low water marks (usage or occupation) of a Pool; Volume size, ...
+\begin{itemize}
+\item a single previous Job
+\item a Volume
+\item a Client
+\item a regular expression matching a Job, Volume, or Client name
+\item the time a Job is on a Volume
+\item high and low water marks (usage or occupation) of a Pool
+\item Volume size
+\end{itemize}
+
The details of these selection criteria will be defined below.
-To run a Migration job, you must have defined a Job resource very similar
+To run a Migration job, you must first define a Job resource very similar
to a Backup Job but with {\bf Type = Migrate} instead of {\bf Type =
Backup}. One of the key points to remember is that the Pool that is
specified for the migration job is the only pool from which jobs will