We have a new application that is making use of both traditional MS SQL and MongoDB for data storage. We're running both instances on the same Windows 2008R2 x64 machine, with 64GB RAM.
There have been some anecdotal reports of poor performance that I've begun to investigate.
I can see that SQL Server is not consuming as much memory as I would expect, and is showing signs of memory pressure.
AppDomain 16 (mssqlsystemresource.dbo[runtime].15) is marked for unload due to memory pressure
In contrast, MongoDB is using a huge working set, which is expected behavior based on the documentation
It relies on Windows to manage memory use.
It seems that SQL server isn't able to, or isn't requesting use any of the memory in the Mongo working set and that is impacting performance. The server is under very low load at the moment.
- Page Life Expectancy seems high at: 1536
- and Buffer cache hit ratio: 404002
- Free list stalls/sec: 695
- Free pages: 26529
Has anyone come across this issue? What it the expected behavior of SQL server in this scenario? I'm considering using the
min server memory configuration option.