Progress
Installation and Configuration Guide
Version 9
for UNIX
Shared Memory and Kernel Configuration
This section applies to shared-memory UNIX systems. Most UNIX systems support shared memory and semaphores; however, if your system does not support them, disregard this section.
In Progress, the multi-threaded architecture makes heavy use of file descriptors, shared memory, and semaphores. Allocation of these resources is controlled by system configuration parameters. On most systems, these parameters are set to values appropriate for Progress applications. However, in some cases, one or more parameters might not be set optimally, thereby limiting the number of Progress users. If you have to reset the parameters, you must edit the parameter file and reconfigure your kernel. The kernel reconfiguration procedure is commonly documented in the system administration manual provided by your hardware vendor.
The optimal parameter settings depend on the system, the application, the number of users, and some minor factors. Table 6–6 lists the crucial parameters and provides guidelines for choosing adequate values for each one.
The parameter settings in Table 6–6 are guidelines. Parameter values near these are acceptable in most cases, but a particular system or application might require increasing the limits.
If shared memory or semaphores are allocated incorrectly, Progress displays an error message when it attempts to start an additional user or server. For example, if SEMMNS is set too low, PROSERVE fails and displays the following message:
Change the relevant parameter values and reconfigure the kernel in response to semaphore or shared-memory errors at startup. Table 6–7 lists the parameters that you might have to raise in response to various Progress error codes.
NOTE: The Blocks in Database Buffers (-B), Lock-table Entries (-L), and Number of Users (-n) startup parameters all affect shared-memory usage. The Number of Users (-n) and Maximum Servers (-Mn) parameters affect semaphore usage (each user or server process uses one semaphore). Before reconfiguring your kernel to increase shared memory or semaphore allocation, see whether you can lower these startup values.
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