Instances of SQL Server have disappeared

Hi,

We had 5 instances of SQL Server running on one of our machines and everything looked to be working fine. Today I installed another instance for a new application and once done and rebooted the new instance didn't show in the SQL Server Enterprise Manager. At this point we decided to uninstall it. After that 4 of the existing instances have diapered as well even though they are running and responding requests from their respective applications.

I did some googling and all I could see is something related to a command called nscontrol but I couldn't find any nscontrol executable on that machine.

Does anyone have any idea what this problem could be?

Thanksnscontrol is related to SQL Notification Services. I don't think that would be part of your solution.

I'm confused why you are installing a new instance of SQL Server for each application?

In any case, are you having any better luck? If not, can you go to the Windows command prompt on the server where SQL Server is running and type in osql -L and see if your instances are all listed? Have you checked your system's event log for any clues? How about the SQL Server error log?

I know that you should be able to run up to 16 instances of SQL Server, so you are probably not hitting that limitation.

Terri|||I'm with Terri. Instead of running 5 instances of SQL Server, why not use 1? And use 5 different databases? Seems like a better solution to me. Probably less overhead too.|||Sorry for not posting sooner, someone here has experienced something similar and the solution was to reregister every instance in Enterprise Manager. We can't explain why this thing happens but looks like this is what had to be done.

With respect to using instances rather then databases, the theory here is that we try to stay away from database administration and delegate it to the groups that actually need that application and databases that is why we give different instances to different groups of people. I hope that this explains somehow our situation.|||Glad you got it sorted out.

Yes, I had done research after you had made that post and read the cases for having multiple instances on the same server. That does make sense. Just keep in mind you can't have more than 16 instances :-)

Terri|||Yes, we knew about 16 instances limit.

Thanks