Starting with version 8.0, Domino is also available as a 64 Bit application for more than System i. If you already run on a 64 bit operating system environment, you will probably consider switching to the 64 bit version of Domino.
A common question is whether Domino 64-bit systems can support more active users, all other variables being the same. Although this is theoretically true, IBM Lotus does not recommend any change to current assumptions made in Domino sizings. Domino 64-bit systems should be sized as Domino 32-bit systems have in the past. Although, that may change as further production deployment experience is gained.
The following list is supposed to provide a better understanding of what you need to be aware of:
- Review IBM Technote 1296452 - FAQ: 64-bit version of Domino http://www-01.ibm.com/support/docview.wss?rs=463&uid=swg21296452
- Domino 64-bit platform is not intended to interoperate with Lotus extended products such as Lotus Sametime and Lotus Quickr. For example, you cannot run Lotus Sametime (a 32-bit application) on Domino 64-bit. For more details, review IBM Technote 1328164 - Support for Lotus Domino Server and companion products on 64-bit operating systems (OS) http://www-01.ibm.com/support/docview.wss?rs=463&uid=swg21328164
- Verify the the Pre-Upgrade Checklists in Domino Deployment especially with regards to 64 bit compatibility
- Review your existing Domino applications and third party add-ons. Existing databases and Java and LotusScript agents within Domino will continue to run successfully. Any C API applications (Domino server add-ins and extension manager DLLs) will need to be rebuilt (compiled and linked).
- Especially on Windows special attention is to be spent on fine tuning Domino to meet the performance expectation. Fore details see IBM Technote 1377517 Constraining the file system cache on 64-bit Windows http://www-01.ibm.com/support/docview.wss?rs=463&uid=swg21377517
We do not recommend to upgrade operating system and Domino at the same time. From a matter of the duration of the change window, it would be best to schedule these two tasks separately.