As you have seen in the kernel system file, there are many kernel tunable parameters. Values of these parameters greatly affect system performance. Some of these parameters are explained in Table 16-1.
Table 16-1. Important Kernel Tunable Parameters
Name
Function
shmmax
Maximum amount of shared memory in bytes
shmseg
Maximum number of shared memory segments that can be attached to a process
maxvgs
The value of the highest numbered volume group
bufpages
Static buffer cache pages
maxfiles
Soft limit to the number of files a process can open
maxfiles_lim
Hard limit to the number of files a process can open; no more open files allowed
nfile
Maximum number of open files on the system at any time
nflocks
Maximum number of file or record locks
fs_async
Enable/disable synchronous disk write
maxuprc
Maximum number of processes per user
nproc
Maximum number of processes that can exist simultaneously on a system
timeslice
Allocation of time slice among competing processes
maxusers
Maximum size of system table
npty
Number of pseudoterminals
maxswapchunks
Maximum amount of swap space that can exist on the system
nswapdev
Maximum number of devices that can be used as device swap
remote_nfs_swap
Enable or disable swap to remote NFS access
Before changing any of these parameters, be sure that you know what is its effect on the system performance.