During my days as a DBA, I frequently received backup files from
my manager, with instructions to restore the contents. Here's
what I usually do to get a handle on things:
·Run RESTORE LABELONLY on
the file
The information provided tells
me if the backup file is the only one in a backup set, or if the
backup file is part of a backup set. The FamilyCount and FamilySequenceNumber columns provide this
information. Recall that a backup may be spread across
multiple files. In such situations, you would need all the
files in order to restore the database successfully.
·Run RESTORE HEADERONLY on
the file
I use this to find out:
·the number of backups that are contained in the file.
A backup file may contain multiple backup sets.
·the backup type, whether if it's a full database backup,
differential, log etc.
·the name of the database that was backed up.
·Run RESTORE FILELISTONLY on
the file
I would only run this on a
full database backup. Running this tells me the number of files
that makes up the database, and the size of each file. This
allows me to know quickly if I have enough disk space to restore
the database.
Can't we tell the size of the
database from the backup file size? No, if:
·the backup file contains multiple backup sets
·the
database contains a lot of truncated data
·the database's tranaction log file contains mostly
truncated data
In summary, there is a wealth of information you can retrieve
from a backup file, using the RESTORE LABELONLY,
RESTORE
HEADERONLY and RESTORE FILELISTONLY
commands. See the Books Online documentation for these
commands for more details.
Document history
6/27/2008 | Initial release. |