It is common for our customers to clone virtual servers.
Sometimes they even clone SQL servers.
We even tell them to do this sometimes, such as when we want to create an identical test environment.
It is a huge time saver, but when cloning a SQL server,
there are a few additional things we need to watch out for. If the customer IT person is not a DBA, they
will most likely have no clue to watch out for these things.
*** If
the SQL server they are cloning has drive mappings or any type of alias to
the storage location where SQL data, log, or backup files reside, these
may need to be re-mapped on the clone.
Before using a cloned SQL server, verify the drives you see are not
really the production drives.
The
easiest way to check is to launch the cloned server and save an empty
text file to each storage location, then launch the production server and
see if you can see the files. If
you can, STOP! It means the new
SQL server may try to modify production data. The SQL services on the cloned server
should be stopped immediately until the problem can be addressed. Each server should have completely physically isolated storage.
*** If
the SQL server has maintenance plans:
Maintenance plans create jobs and have a hardcoded connection
string to the jobs they create. On
the cloned server, these connection strings will point to the production
server. This may cause SQL jobs to fire
twice. This will be noticeable for
backup plans because there will be 2 nighty backup files generated, or job
failures due to conflicts. This
will also degrade performance during the day on the production
server.
The
correct way to prevent this starts BEFORE the cloning. Record the steps in the maintenance
plans on the production server, then disable all the plans and jobs on
the production server before cloning it.
Re-enable them after cloning is complete. Then on the clone server, delete the
maintenance plans and re-create them.
Check all the other jobs to make sure their connection (bottom
left of the job properties window) is correct before re-enabling them.
