Explanation:
notes.ini SERVER_MAX_CONCURRENT_TRANS and notes.ini SERVER_POOL_TASKS settings
work together to determine how many NRPC threads can be actively processing
server transactions. In most environments, these settings will not need
adjustment. These settings should only be adjusted under the direction
of IBM Support. Generally, IBM Support will have found evidence that
the MaxConcurrentTrans bottleneck is adversely affecting the performance
of a heavily loaded server.
Note: The Domino server on zSeries and zLinux differ in their configuration
from other platforms in the following way. Both are allowed unlimited MaxConcurrentTrans,
and their thread pool size defaults to 100 threads for zSeries and 40 threads
for zLinux. These thread pool sizes can be adjusted using the INI Server_Pool_Tasks,
but it is not recommended to change these values.
Default:
For Domino 6.x through 8.5 under OS390
The default value of SERVER_MAX_CONCURRENT_TRANS is -1
The default value of SERVER_POOL_TASKS is 100
For Domino 6.x through 8.5 under zLinux
The default value of SERVER_MAX_CONCURRENT_TRANS is -1
The default value of SERVER_POOL_TASKS is 40
For Domino 7.0.3 through 8.5 under OS400
The default value of SERVER_MAX_CONCURRENT_TRANS is -1
The default value of SERVER_POOL_TASKS is 40
For Domino 6.x through 7.0.4 under all other Operating Systems
The default value of SERVER_MAX_CONCURRENT_TRANS is 20
The default value of SERVER_POOL_TASKS is MIN(100, 2 * SERVER_MAX_CONCURRENT_TRANS)
For Domino 8.0 through 8.5 under all other Operating Systems
The default value of SERVER_MAX_CONCURRENT_TRANS is MIN(100, 20 * number_of_cpu)
The default value of SERVER_POOL_TASKS is MIN(100, 2 * SERVER_MAX_CONCURRENT_TRANS)
Recommendation:
Using/adjusting these settings should be avoided unless specifically directed
to by IBM Support. Both SERVER_MAX_CONCURRENT_TRANS and SERVER_POOL_TASKS
are high leverage configuration options. They are also dangerous when used
incorrectly.
Note: It is possible that for pre-8.0 versions of Domino with multiple
CPUs, under an operating system other than OS390, OS400 and zLinux, there
may be benefit from running with non-default values for SERVER_MAX_CONCURRENT_TRANS
and SERVER_POOL_TASKS. It is possible that in order to keep multiple CPUs
busy, the configured values would be higher than the defaults.
Never explicitly use SERVER_MAX_CONCURRENT_TRANS=-1. This option allows
unlimited thread spawning under most OS.
Never set SERVER_MAX_CONCURRENT_TRANS without also setting SERVER_POOL_TASKS,
and vice versa.
It is strongly recommended to never configure more than 100 threads total
across all Notes Ports.
Whenever making any changes to SERVER_MAX_CONCURRENT_TRANS and SERVER_POOL_TASKS,
carefully test the configuration before deploying it to production servers.
Related Settings:
Server_Pool_Tasks, Server_Max_Concurrent_Trans,
_PortThreadPoolCount
References:
Technote
1207456: Using the Domino server INI parameter Server_Max_Concurrent_Trans
Technote
1220856: How to set the NRPC thread pool sizes for each Notes port in Notes
Domino 7
Technote
1234550: Domino Server Performance Troubleshooting Cookbook
Domino Configuration Tuner:
This setting is included in the DCT
catalog of best practices.