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

Daniel Nashed  17 April 2009 10:58:16

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


Comments

1Matthias  17.04.2009 13:15:06  Shared Memory Size by default limited to 2GB in Domino 32bit on Win64

and why do you run a 32bit domino on a 64bit windows? Where is the sence of this???

2Tim E. Brown  17.04.2009 14:17:43  Shared Memory Size by default limited to 2GB in Domino 32bit on Win64

Is Windows 2003 64 bit Domino 8.5 not ready for primetime yet?

What about Windows 2003 64 bit Domino 8.0.2? Are there any large customers doing it?

TIA,

Tim E. Brown

3Sjaak Ursinus  17.04.2009 14:42:50  Shared Memory Size by default limited to 2GB in Domino 32bit on Win64

Daniel,

Is this only possible on Win64 system ? I mean this should also be possible on a Win32 system ? as it is possible to run your windows environement with the /3GB or the /4GT switch. Which makes it possible to address more space to the user Space of a process.

Which suggests that using one of these 2 switches (Win2000 or Win2003) wouyld allow you to upscale your use of Shared Memory to Domino on older platforms as well ?

4John Rowland  17.04.2009 14:58:51  Shared Memory Size by default limited to 2GB in Domino 32bit on Win64

@1 I have recently encountered one such instance: 32bit Domino on 64bit Windows 2003R2 is required by BES. Installing 64bit Domino is is unsupported and will fail the BES install.

5Pablo  17.04.2009 15:26:57  Shared Memory Size by default limited to 2GB in Domino 32bit on Win64

I think that sametime is not migrated to x64... so that's why you will need to run Domino x86 in an x64 computer.

Also most of the antivirus vendors did not yet migrate to x64 or they migrated to it but they didn't fully test it.

6Daniel Nashed  23.04.2009 1:40:39  Shared Memory Size by default limited to 2GB in Domino 32bit on Win64

@Matthias, sorry for the late reply but I unread marks did not work because of the blocked spam posts ...

You gain 2 GB of memory using 64bit windows because this allows to use the full 32bit address space for the application instead of 2GB for application and 2GB for system on 32bit.

There are ways to allow more memory on Win32 like /3GB witch but those do not give more performance because they sort of emulate the bigger address space.

You really need to run on a 64bit. Windows is the last platform that moves to 64Bit OS. AIX, Solaris and Linux are alread there. And iSeries already runs with a larger address space for a long time also native for the Domino application.

So you get 90% of the benefits right now form switching to a 64Bit Windows OS and there is currently no need to run Domino 64bit native for most environment.

it only makes sense on extreme alrge HTTP or Mail-Servers with a large local process memory needed.

-- Daniel

7Daniel Nashed  23.04.2009 1:46:44  Shared Memory Size by default limited to 2GB in Domino 32bit on Win64

@sjaak, all the ways to allow more memory on a 32bit OS like /3GB and PAE are like a hack. I would not use /3GB at all. PAE works better and there is a whitepaper for Notes on Citrix mentioned earlier in my blog that does test a 32Bit Citrix Server with PAE to allow more memory.

But sitll the right way to go for a Domino server is 64Bit.

-- Daniel

8Fabio Santos  16.10.2012 22:11:56  Shared Memory Size by default limited to 2GB in Domino 32bit on Win64

What about Domino R7? Can we use the same parameter?

9Santhosh  12.05.2014 15:02:25  Shared Memory Size by default limited to 2GB in Domino 32bit on Win64

Hello

Is there as way of allocating more memory on a Windows 2012 R2 box for Domino 64 server bit running 9.01?

10Daniel Nashed  16.05.2014 0:02:24  Shared Memory Size by default limited to 2GB in Domino 32bit on Win64

On Domino 64 you don't have those kind of limitations. The pointers used are 64bit.

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