Milestone Central 3.7 - Manual (Page 71)

Milestone XProtect 3.7; Administrator’s Manual
Backing Up & Restoring the XProtect
Central Database
Why Back Up?
The XProtect Central Server stores data in a database. The database can be stored in two different
ways:
• Network SQL Server: You have chosen to store XProtect Central data in a database on an
existing SQL Server on your network. When that is the case, XProtect Central simply points
to the database’s location on the SQL Server.
• SQL Server Express Edition: You have chosen to store XProtect Central data in a SQL
Server Express Edition database on the XProtect Central Server itself.
Regularly backing up your XProtect Central database is always recommended: Having a backup
gives you the ability to restore your XProtect Central data—primarily alarms—in a disaster recovery
scenario. However, backing up also has the added benefit that it flushes the SQL Server’s
transaction log.
What is the SQL Server transaction log, and why does it
need to be flushed?
Each time a change in the XProtect Central data occurs, the SQL Server will log the change in its
transaction log—regardless whether it is a SQL Server on your network or a SQL Server Express
edition. The transaction log is essentially a security feature that makes it possible to roll back and
undo changes to the SQL Server database. The SQL Server by default stores its transaction log
indefinitely, and therefore the transaction log will over time build up more and more entries.
The SQL Server’s transaction log is by default located on the system drive, and if the transaction
log just grows and grows, it may in the end prevent Windows from running properly. Flushing the
SQL Server’s transaction log from time to time is thus a good idea; flushing it does not in itself
make the transaction log file smaller, but it prevents it from growing out of control. XProtect
Central does not, however, automatically flush the SQL Server’s transaction log at specific
intervals. This is because users have different needs. Some want to be able to undo changes for a
very long time, others do not care; what would suit one organization’s needs could be problematic
for others.
You can do several things on the SQL Server itself to keep the size of the transaction log down,
including truncating and/or shrinking the transaction log (for numerous articles on this topic, go to
support.microsoft.com and search for SQL Server transaction log). However, backing up XProtect
Central’s database is generally a better option since it flushes the SQL Server’s transaction log and
gives you the security of being able to restore your XProtect Central data in case something
unexpected happens.
Prerequisites
You will need:
• Microsoft ® SQL Server Management Studio Express, a tool downloadable for free from
www.microsoft.com/downloads. Among its many features for managing SQL Server
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