There may be a situation when Skype for Business front end server despite of having enough memory performs very poorly and you can even see low memory errors in Event Log from SQL. In case the front end is hosted on virtual machine the first thing that has to be checked in such kind of scenario is MS SQL Server memory limits. These limits are set by Skype for Business Deployment Wizard at the moment of database installation and in case the virtual machine has dynamic RAM and amount of actual RAM was not maximum at the moment of deployment SQL Server memory limits could been set incorrectly.There are no official information about recommended values but experimentally I found that values should be:
| Instance | Min. Memory | Max. Memory |
| RTCLOCAL | 12% of installed RAM | 15% of installed RAM |
| LYNCLOCAL | 6% of installed RAM | 8% of installed RAM |
So if we have 16 Gb = 16384 Mb installed on front end server the values should be set as following:
You can set this manually with SQL Management Studio or configure server to use static memory and run Deployment Wizard step one. Then change memory type back to dynamic if this is desired configuration.
