Overwrite/restore system databases

Question

Hi,

We had a crash and needed to rebuild the cluster and install SQL Server. We still have old master/msdb mdf/ldf files and also have the week old backups of system databases. Can we do the following (http://msdn.microsoft.com/en-us/library/ms190190.aspx):

1. Take a copy of current mdf/ldf files (if required later)
2.  Stop sql server and agent
3. Overwrite master,msdb and model mdf/ldf files
4. Restart SQL Server

or

for step 3 we should not overwrite the mdf/ldf files and use the backups of system databases of 1 week old

or

we should not restore master and only use the above for msdb if restoring master can cause any other issue

Answer 1

You can replace the old master, msdb mdf and ldf file provided the SQL Server build is the same as earlier, meaning if the SQL instance before crash was on build 10.50.2500 then you will need to get the new SQL instance up to the same build 10.50.2500

Answer 2

Hi Harvinder

Yes you can overwrite but  if build is same and if its different then you can first restore system databases on your new instance  as user database and then replace mdf and ldf files

refrence : http://saurabhsinhainblogs.blogspot.in/2012/09/knowledge-sharing-restoring-system.html

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Thanks
Saurabh Sinha
http://saurabhsinhainblogs.blogspot.in/
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Answer 3

why dont you restore the system databases

http://sqlservr.blog.com/2012/05/09/how-to-restore-system-database-in-2-steps/

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Ramesh Babu Vavilla MCTS,MSBI