Adjusting System Parameters
As indicated above, the UNIX system parameters that need adjustment are used to control resource consumption on a user, process, or system-wide basis. In the case of either a user or a process parameter, the new value for the parameter should be the larger of the existing value or the Calendar Server requirement. In the case of a system-wide parameter, the Calendar Server requirement must be added to the existing value to calculate a new value.
Assume that Corporate-Wide Services is disabled and let the term "SONOFF" denote the maximum number of simultaneous log-ons and log-offs to the Calendar Server. Observe that under extreme situations, i.e. power failure, all Calendar Server sessions will be terminated in rapid succession. Thus, in the worst case "SONOFF" is as large as lck_users. The Calendar Server requires at least the following resources:
If Corporate-Wide Services is enabled, further resources are required:
Finally, consider the Message and Semaphore resource requirements of the Calendar Server, which are independent of Corporate-Wide Services:
The memory allocation in bytes as related to the Calendar Server Lock Manager daemon (unilckd):
400KB * lck_users
A final comment concerning the Calendar Server engine's daemon/servers uniengd: this executable has been compiled (cc) in share mode (-n) insuring that all concurrently executing copies of uniengd share a single instruction section (sometimes called "Program text segment"), thus saving memory.
Note
The system clock must be running and properly set for the proper function of the Calendar Server.
Adjusting the HP-UX Kernel Parameters
The following section describes the maximum kernel requirements, and as such should apply to most HP-UX installations. All of the above parameters can be modified via SAM, a menu-based system administration manager.
The assumptions concerning the Calendar Server unison.ini file parameters are:
The following is a actual example involving 500 users:
/etc/system file with a standard text editor like vi. All of the parameters are set using the following syntax:
e.g.:
set maxuprc=2641
set max_nprocs=2636
In addition, the message queue and semaphore parameters must include the name of the specific module to be modified. The syntax is as follows:
e.g.:
set msgsys:msginfo_msgmni=351
set semsys:seminfo_semmni=345
In order for the above changes to take effect, reboot the system with the '-r' flag.
To see a complete list of the tunable kernel parameters, run the nm command on the appropriate module. For example:
% /usr/ccs/bin/nm /kernel/unix
To see the current values assigned to the kernel parameters, use the sysdef command. For example:
% sysdef -i
In the NEW column below, the max function returns the maximum of the two entries.
Note
The maximum number of open files is unlimited under SunOS, and therefore does not need to be set.
The following is an actual example with 500 users:
maxuprc (maximum number of processes per user-ID) which can be modified via SMIT (AIX's menu-based system administration utility) or the command line utility chdev.
To see a complete list of the parameters and their current values, run the lsattr command:
% /etc/lsattr -E -l sys0
To see the current values assigned to a particular kernel parameter, use the lsattr command with the parameter name. For example:
% /etc/lsattr -E -l sys0 -a maxuproc
To change the value of the maxuproc parameter, use the chdev command. For example:
% /etc/chdev -l sys0 -a maxuproc = 200
As stated above, the AIX kernel dynamically allocates and reallocates resources as they are needed up to a predefined limit. The known limits of the parameters are as follows:
The practical limits of the Calendar Server, defined as the maximum number of concurrent users on a system, are effectively determined by the upper limits of the maximum number of open files. Assuming there are no other activity or resource requirements on the system, the maximum number of concurrent users (lck_users) under AIX is approximately 10000*20+60=200060.
Additional Reading
For more information on AIX Performance Tuning and Administration, please consult AIX Performance Tuning by IBM, Prentice Hall, 1996.
For more information on modifying the kernel parameters under SunOS, refer to Administering Security, Performance, and Accounting by Sun Microsystems, Inc.
HP-UX system parameters are described in Appendix A, System Parameters, of the HP-UX manual entitled System Administration Tasks.
An excellent source of general information on this topic is System Performance Tuning by Mike Loukides, O'Reilly & Associates, Inc., 1991.