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FAQ: 64-bit version of Domino

Technote (FAQ)


This document contains answers to frequently asked questions about 64-bit Lotus® Domino® server.


Question: Does Domino run as a 64-bit application?
Answer: Domino 8.0.1 and 8.0.2 runs as a 64-bit application on the following 64-bit operating systems (OS):

  • 64-bit IBM AIX 5.3
  • 64-bit IBM AIX 6.1
  • Microsoft® Windows® 2003 Server x64 Edition
  • i5/OS® (all versions)1

In addition, Domino 8.5 runs as a 64-bit application on zLinux.

See the Release Notes for details about platforms and system requirements:

Question: What are the advantages of running 64-bit Domino?

Answer: The objective of 64-bit Domino is to provide memory relief for customers who today are experiencing problems such as crashes, or system hangs due to out of memory conditions. Several customers are experiencing such issues where memory limitations especially on Windows and AIX result in such problems. If you are currently running 32-bit Domino on AIX or Microsoft® Windows® 64-bit platforms, and you are experiencing low memory issues, then using 64- bit Domino on Windows 2003 64-bit relieves this memory issue. In the case of AIX, 64-bit Domino is required for relief.

On Windows: 32-bit Domino on 64-bit Windows can obtain ~4GB of memory from the OS. 64-bit Domino on 64-bit Windows can obtain much more from the OS.

On AIX: If you were constrained by memory segments running 32-bit Domino on 64-bit AIX, then 64-bit Domino can help with that constraint.

Essentially, in 64-bit Domino, both OS memory limits and internal Domino memory limits have been greatly expanded, and this helps with memory issues that might be experienced with 32-bit Domino.

Question: Is IBM planning a 64-bit version of Domino for x86 Linux (SLES or RHEL)?

Answer: The primary reason for 64-bit Domino is memory relief. Domino 32-bit running on SUSE Linux Enterprise Server and Red Hat Enterprise Linux (x86) already gets 4GB of memory for the Domino process and does not have the same memory constraints of some other platforms. IBM is reviewing plans for 64-bit Domino on SLES and RHEL in a future release of Domino.

Switching from 32 bit Linux to 64 bit Linux years ago, when all we had was 32 bit Domino, was a workaround to the 3GB limit that 32 bit Linux imposed. Since that time, Linux has removed the 3GB limit and now gives a 32 bit application 4GB of memory in both 32 bit and 64 bit Linux. Benefits of using 64 bit Linux instead of 32 bit Linux continue to be that 64 bit Linux is more efficient at addressing memory and uses 64 bit drivers for disks. These tend to give you better performance in file caching and disk I/O management which help the performance of Domino. Even though 32 bit Domino can only access 4GB of memory, systems running 64bit Linux with 16Gb of memory can efficiently use the remainder of memory as File cache, dramatically reducing the amount of disk reads Domino requires, especially on mail servers. This shows up as better response time to the Domino mail users.

Question: Have performance tests been conducted for 64-bit Domino?

Answer: Yes. Performance tests comparing 64-bit Lotus Domino 8.0.1 server performance against 32-bit Lotus Domino 8.0.1 verified that 64-bit Domino has equivalent CPU performance with 32-bit Domino on both AIX and Windows for equivalent Lotus Notes® client loads and no substantial resource penalty.

Question: Is there any change to current assumptions on Domino sizings?

Answer: A common question is whether Domino 64-bit systems can be planned to 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.

Question: What are the future plans for 64-bit Domino?

Answer: Further 64-bit Domino development will be based on customer demand. IBM Lotus will respond to customer driven needs regarding 64-bit Domino. For example, there is currently no exploitation of 64-bit support by Domino in 8.0.1, such as increased cache sizes. IBM is anticipating and planning for exploitation requests for future versions of Domino.

Question: Now that Domino is 64-bit, what happens to 32-bit Domino on either the 32-bit or 64-bit platform?

Answer: IBM offers a choice. For as long as the 32-bit version of Domino is actively in market, you will have the flexibility to run 32-bit Domino on a 64-bit platform, or make the move to 64-bit Domino. The implication is that there is some time to plan and prepare for your transition to 64-bit Domino. The 32-bit version of Domino is still actively in market, and will be for the foreseeable future. This will be evaluated in the future based on market demand of the operating systems.

Question: How does Domino on i5/OS (and related products) fit into this 64-bit strategy?

Answer: The i5/OS platform runs only on 64-bit hardware and has been enabled for 64-bit for a long time. This means that all software applications that run on i5/OS, including Domino, Lotus Enterprise Integrator (LEI), Lotus® Sametime®, Lotus® Quickr™, Lotus® QuickPlace®, and Lotus Document Manager are 64-bit capable and have been for a long time.

Question: How can I determine if I am running 64-bit Domino?

Answer: You should first check the version of the OS, then check for the version of Domino.
    Check the OS to confirm 64-bit platform
    • For Microsoft Windows Vista™ and Microsoft Windows 2003 operating systems refer to Microsoft document "How to determine whether your computer is running a 32-bit version or a 64-bit version of the Windows operating system" (#827218) for detailed information.
    • For other operating systems refer to the document, "How to determine if the operating system is running in 64 bit mode" (#1114965).

    Check the version of Domino
    • At the server console type sh stat server. There is a server statistic called "Server.Version.Architecture" that indicates if Domino is 64-bit.
    • The server console will display Server name: Lotus Domino Server (64-bit) at the top of its window.

    Note: Server.Version.Architecture incorrectly reports 32-bit on i5/OS on some earlier versions of Domino for i5/OS. Domino for i5/OS is ONLY available in 128 bit and will be displayed correctly on the console with Domino 8.0.2 and 8.5 and later versions.

Question: What things do I need to consider before I deploy 64-bit Domino?

Answer: You must have 64-bit hardware and it must be running a supported 64-bit OS (see the first question/answer above for a list of supported platforms). You must obtain 64-bit Domino related software (for example, addins, backup software, anitvirus, and so on) and not just 64-bit Domino. You cannot use 32-bit Domino related software with 64-bit Domino. Only 64-bit addins and Domino related software can be run with 64-bit Domino. For example, you will need a 64-bit version of LSX, where there are shared libraries . You will need 64-bit versions of Sametime and Quickr when they become available. Not all third party products support 64-bit yet, so be sure to check with the third party vendor.

You need to review your existing Domino applications. Existing databases and Java and LotusScript agents within Domino will continue to run successfully. Any C API applications (Domino server addins and extension manager DLLs) will need to be rebuilt (compiled and linked), however.

Question: What does the install of Domino 64-bit look like?

Answer: Visually, the install screens look the same as if you were installing 32-bit Domino. Once you launch the Domino 64-bit server, you will know it is 64-bit because "(64-bit)" is displayed in the Domino server console.

Question: Can you run a mixed Domino cluster with 32-bit and 64-bit Domino?

Answer: Yes. Clustering works uniformly in 32-bit and 64-bit Domino and in a mixed environment.

Question: Can 64-bit Domino be installed on partitioned servers?

Answer: Yes. However, for both Windows and UNIX, when you install on a partitioned server, all partitions must be upgraded and will be 64-bit. You cannot upgrade just one partition. All partitions must be either 32-bit or 64-bit.

There is a workaround to this rule on UNIX only. On UNIX 64-bit, you have the option of running different versions (32-bit Domino and 64-bit Domino) on your partitions. You can do this if you install the 64-bit binaries to a separate location. For example, your 32-bit server has binaries in /opt/ibm/lotus, Data directories are /opt/notesdata1 and /opt/notesdata2. To upgrade only one partition and still run 32-bit in the other, you would install the new binaries somewhere else, such as /opt/ibm/lotus64 , and then specify only one of the partitions for the upgrade, making sure each data directory runs the appropriate binaries.

Question: How do I upgrade from my existing 32-bit Domino to 64-bit Domino?

Answer: Install 64-bit Domino over your existing 32-bit Domino. The installer will try to first uninstall the 32-bit Domino.

Note: In the case that you have a previous w64 installation coexisting with the w32 installation, the installer first finds the w64 install and skips the uninstall of w32. However, later on, the installer discovers the w32 installation and gives this warning, "W32 bit version of Domino is currently installed. Upgrading to 64 bit Domino is not supported. Please uninstall the W32 bit Domino Version first"

Make sure all partitions are upgraded.

Question: Is there any parameter I should consider applying to 64-bit Domino for performance issues?

Answer: The following NOTES.INI parameter may be used for both 32-bit Domino and 64-bit Domino running on 64-bit Windows. It addresses a 64-bit Windows situation where the Windows file system cache may affect applications running on the platform.


This parameter may be used to adjust the maximum percent of physical memory that can be used, and it should be considered in cases where the file system cache is not being set correctly by default at Domino startup. Please see the Notes/Domino 8.0.1 Release Note "Constraining the file system cache on 64-bit Windows" for more details. Note: The initial version of the Release Note content incorrectly identified the default value for this parameter as 70%. The default is actually 30%. For the latest copy of the release notes go here. For more information regarding Windows 64-bit system cache, see

Question: What is the optimum value for constrained shared memory for a 64-bit Domino server?

Answer: This depends on the load on the data directory as in all previous releases.

Question: Are there any new memory parameters for 64-bit Domino?

Answer: There is nothing specific to 64-bit Domino. However, it is no longer necessary to use previous memory related NOTES.INI parameters such as ConstrainedSHM=1 or PercentAvailSysResources.

Question: Are the Notes.ini parameters, AIX_LIMIT_SHM_SEGMENTS and AIX_VERY_LARGE_MM, correct to use on 64-bit Domino for AIX? Do they have any effect?

Answer: These variables are no longer needed and should not be used if running 64-bit Domino on AIX. The variable, AIX_VERY_LARGE_MM, should actually not be used even in 32- bit Domino unless absolutely necessary as there are issues with using it (certain AIX functions have issues).

For more information about AIX_LIMIT_SHM_SEGMENTS and AIX_VERY_LARGE_MM, refer to document "AIX_LIMIT_SHM_SEGMENTS used to control shared memory on Domino/AIX." ( #1253505).

Question: What Domino extended products work with 64-bit Domino?

Answer: At 64-bit Domino 8.0.1 release, DECS and LEI are supported with 64-bit versions of Domino on Windows 2003 64-bit only. Sametime and Quickr do not have 64-bit versions at this time.

Question: Is DB2NSF supported on 64-bit Domino?

Answer: No, DB2NSF is not supported on 64-bit Domino. DB2NSF is supported only on 32- bit Domino.

Question: Is there any functionality unique to 64-bit Domino that is not available in 32-bit Domino?

Answer: 64-bit Domino is unique in that it has substantially more addressable memory than 32-bit Domino.

1The i5/OS platform runs only on 64-bit hardware and has been enabled for 64-bit for a long time. i5/OS also provides 128-bit pointer capability. This means that all software that runs on i5/OS, including Domino, LEI, Sametime, Quickr, QuickPlace and Document Manager is 64-bit capable and typically uses 128-bit pointers.

Related information

Considerations when developing Domino C and C++ API app
How to determine if the operating system is running in
A simplified Chinese translation is available

Document information

More support for: IBM Domino

Software version: 8.0.1, 8.0.2, 8.5

Operating system(s): AIX, IBM i, Windows

Reference #: 1296452

Modified date: 15 April 2010

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