Improving server capacity and response time

These tips for improving server capacity and response time come from the analysis of NotesBench reports, which are published by NotesBench Consortium members. Some of this information may derive from earlier versions of Domino, and, therefore, may not be completely applicable to Lotus Domino 6.

Make sure your server memory matches the number of users you want to support. Most NotesBench vendors use 300K to 400K per active user. They also set their NSF_BUFFER_POOL_SIZE to the maximum for their memory configuration. This setting isn't necessary, because the Domino server initially obtains a third of available memory and grows only if necessary (depending on the load). You should use published physical memory configurations as a ceiling for memory configuration decisions.

1. Make I/O subsystem improvements. For example you can:

• Move from EISA-based systems (such as, controllers) to PCI-based systems
• Exchange EISA/PCI boards for PCI-only boards (this way, lower speed EISA devices won't decrease the I/O throughput)
• Use stripping to balance the load across all drives in the array. Use hardware RAID, such as RAID 0+1, to improve performance and availability.
• Use multiple I/O controllers to distribute logical volumes (and use file pointers to databases across separate controllers). Make sure you have the latest BIOS for your I/O subsystem. This is an inexpensive way to remove a likely throughput bottleneck.

3. Increase the stripe size. Refer to the NotesBench reports to see what the vendors use. NotesBench vendors use a stripe size of 8K (Hewlett-Packard systems) or 16K (IBM NetFinity® reports). (The IBM NetFinity report provides additional information on I/O settings such as IOQ Depth, Outbound Posting, PCI Line Prefetch, and Address Bit Permitting.)

4. Use faster CPUs. NotesBench vendors have moved beyond the Pentium®, Sparc®, and PowerPC® processors, which were in the 100Mhz to 200Mhz range, to higher speed processors. However, they consistently use P6-based systems over the Pentium II systems for high-end Domino server loads. The size of your Level 2 cache should match your expected user loads and the response time you want. Vendors have moved from 256K to 512K, 1MB to 2MB Level 2 cache systems, especially on their greater than two-CPU configurations.

5. Improve your network. NotesBench vendors have:

• Moved from 10Mbps cards and networks to 100Mbps configurations
• Used multiple LAN segments (one for each partition) to isolate network traffic, at the high-end user loads

7. You can improve Web server performance by disabling HTTP server logging. Logging options are stored in the Server document. In the HTTP server "Enable logging to" section are two fields, Log files and DOMLOG.NSF. Disabling both of these fields improves Web server performance.

8. You can improve general server performance by disabling the type-ahead mail addressing feature. (Type-ahead allows users to enter the first few characters of a user's name; the server then completes the rest of the name automatically.) To disable type-ahead on a server, open the server's Configuration Settings document in the Domino Directory. On the Basics tab, choose Disabled in the Type-ahead field. Then save and close the document.

NOTES.INI settings that affect Domino server performance

Replicators

This setting specifies the number of Replicator tasks that can run concurrently on the server. The default is 1. Typically, the number of replicators should equal the number of processors on the server. However, hub servers can run more replicators.

Server_Availability_Threshold

This setting specifies the acceptable level (a percentage) of system resources available to a server. By setting this value for each server in a cluster, you determine how the workload is distributed among cluster members. The default is 0, which indicates a fully available state (workload balancing is disabled). A value of 100 indicates the server is busy; the Cluster Manager then tries to redirect user requests to more available cluster members.

Server_MaxUsers

This setting sets the maximum number of users that are allowed to access a server. When this number is reached, the server state becomes "MaxUsers," and the server stops accepting new Database Open requests. The default is 0 (unlimited access to server by user). By setting a maximum number of users allowed on the server, you can prevent server performance from degrading because of demand overload.

Server_Session_Timeout

This setting specifies the number of minutes of inactivity after which the server automatically terminates network and mobile connections. The minimum recommended setting is 15 minutes. If you specify a lower time, the server must reopen database server sessions too frequently, which slows server performance. For best performance, the recommended time is 45 minutes.

For mobile connections, X.PC has its own internal time out. If the X.PC time-out value is shorter than the Server_Session_Timeout value, the X.PC time out takes precedence.

ServerTasks

This setting controls the tasks that the server runs. These tasks start automatically at server startup and continue until the server is shut down. Improve performance by removing tasks that aren't appropriate to the server. Do not remove the Update task from a server. If you do so, the Domino Directory will not update.

Translog_Status

This setting enables transaction logging for all Release 5 and later databases on the server. Default is 0 (transaction logging disabled). Set this to 1 to enable transaction logging. Transaction logging improves the availability and reliability of the server.

Note You must upgrade databases to Domino Release 5 or later format before they can use transaction logging.

See Also

Improving Domino server performance
Improving partitioned server performance and capacity
Tools for measuring server performance