Shared Memory Size by default limited to 2GB in Domino 32bit on Win64

Daniel Nashed  17 April 2009 08:58:16

Even Domino 8.5 32bit on a Windows 64bit OS can address up to 4 GBs, by default the shared memory is limited to 2GB.
If the server tries to allocate more memory the allocation will fail.

To allow the server to use more shared memory (usually you need less than 1 GB for local process memory per process) you can increase the shared memory that can be allocated thru a notes.ini parameter ConstrainedSHMSizeMB=3072.
Note: You should not set ConstrainedSHM=1 because it will enforce the default values of 2 GB.
You should not allow the server to use much more than 3 GB shared memory because that would leave too less memory for servertask like HTTP and Mail Router.
We ran into this testing memory limits on a Domino 8.5 machine on Win64 and it does not look well documented. IMHO the default on Win64 should be 3 GB.

Normally 2 GB of shared memory will be OK for most servers but in case your server needs more memory and this parameter is not set the server might crash or hang.

-- Daniel

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