The OER specifies the minimum memory requirements for a desired deployment size.

SQL Server allows you to customize the memory limit, to make sure the server will never consume all system memory.

Consult the following Microsoft documentation to set the maximum amount of memory:

http://technet.microsoft.com/en-us/library/ms191144(v=sql.105).aspx

The following table outlines how much memory should be made available to SQL Server, for different deployments:

Deployment Required total RAM on the server Memory Limit to Set for SQL Server
101 – 250 endpoints 12 GB 8 GB = 8192 MB
251 – 2,000 endpoints 16 GB 12 GB = 12288 MB
2,001 – 5,000 endpoints 32 GB 27 GB = 27648 MB
5,001 – 20,000 endpoints 48 GB 38 GB = 38912 MB
20,001 – 30,000 endpoints (SQL Standard) 128 GB 118 GB = 120832 MB

10,001 – 40,000 endpoints

(SQL Enterprise)

64 GB 54 GB = 55296 MB

Over 40,000 endpoints

(SQL Enterprise)

96 GB 86 GB = 88604 MB
Note: Deployments smaller than 100 endpoints require SQLExpress only, which has a built-in maximum memory cap of 1 GB.

In order to restrict SQL memory usage, you can run following query from SQL management Studio (replacing the highlighted number with number of megabytes from the table above):

EXEC sys.sp_configure N'show advanced options', N'1'  RECONFIGURE WITH OVERRIDE
GO
EXEC sys.sp_configure N'max server memory (MB)', 53248
GO
RECONFIGURE WITH OVERRIDE
GO
EXEC sys.sp_configure N'show advanced options', N'0'  RECONFIGURE WITH OVERRIDE
GO