Domino 32 bit vs 64 bit – what’s the difference?

I have been absent for a while but with good reason – a new project that keeps me VERY busy.

Being busy though also has it’s advantages though, since it also means that I get to be exposed to allot of new things and learn more and more.

So, 32 bit vs 64 bit – what is the difference? Well, first of all let’s state that I am talking about Domino on Windows. To run 64 bit Domino you require 64 bit OS. What that also means is that any add-in tasks that you want to run inside of Domino will also need to be 64 bit – 32 bit 3rd party processes will not run on a 64 bit Domino/Windows server.

What is it that you gain? Well, the main gain you get is shared addressable space. Under 32 bit domino the maximum shared address space you get is 2 GB. that means that any add-in task you run (such as an anti virus product etc.) has a maximum shareable shared address space of 2 GB. On a busy server that can can be tight. The reason I know that is that in the first week I started my present project we saw what happens to a server that runs out of available shared address space – it will will present you with a crash and a wonderful NSD file ….

Now, when you change to 64 bit you now double your shared addressable space to 4 GB. this gives you PLENTY of space for a busy server (user sessions, applications, third party add-ins, etc.).

I will blog more about this topic in the near future and hopefully be able to shed some more light on this interesting subject.

5 thoughts on “Domino 32 bit vs 64 bit – what’s the difference?

  1. “…when you change to 64 bit you now double your shared addressable space to 4 GB.”

    Shared addressable space in 64-bit operating systems is significantly greater than 4GB. According to msdn: “By default, 64-bit Microsoft Windows-based applications have a user-mode address space of 8 terabytes”


    • Nathan!
      Yes, Windows 64 bit allows that – however I was talking about Domino addressable shared memory. Due to the way that the memory handles in domino are programmed (they are predominantly 32 bit, even in the 64 bit Domino version) 4 GB is all you get in domino. Other 64 bit products on Windows might be able to share up until that advertised 8 terabytes but when it comes to Domino, 4 GB of shared address space is all you get until IBM/Lotus decides to do some fundamental changes to their memory handling in the core Domino program.


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