nflocks(5) [hpux man page]
nflocks(5) File Formats Manual nflocks(5) NAME
nflocks - maximum number of file locks VALUES
Failsafe Default The default value is computed at runtime and depends on the amount of physical memory on the system. For small memory systems (less than 1GB), the default is 1200. For systems with more than 1GB of memory, the default is 4096, or 4K. Allowed values The minimum value is 50. The maximum value is 0x1000000. Specify a positive integer value. DESCRIPTION
The tunable represents the maximum number of file locks that are available system-wide. Who Is Expected to Change This Tunable? This tunable should be changed on systems expected to run applications with large number of file locks. When changing this number note that one file may have several locks, and databases that use or may need an exceptionally large number of locks. Restrictions on Changing This tunable is dynamic (tuning will take effect immediately on the running system). When the value of is dynamically tuned it cannot be set to a value lower than the current number of file locks in the running kernel. When Should the Value of This Tunable Be Raised? The value should be increased when large numbers of file locks are expected to be used simultaneously. What are the Side Effects of Raising the Value? The kernel allocates a portion of memory proportional to the new value of and frees memory proportional to the old value. Additional mem- ory is consumed as new locks are created. When Should the Value of This Tunable Be Lowered? The value can be lowered to limit the number of available file locks on a system and reduce memory consumption. What are the Side Effects of Lowering the Value? The kernel allocates a portion of memory proportional to the new value of and frees memory proportional to the old value. Additional mem- ory may be released to the system to be used for other purposes if the usage was ever higher than this new value. What Other Tunable Values Should Be Changed at the Same Time? None. WARNINGS
Setting to the maximum value(0x1000000) will result in a large memory allocation (~.5GB). A request to change the value of will fail with set if there is either not enough free memory or the remaining free memory would be so small as to potentially hinder system performance. All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its meaning changed in future releases of HP-UX. Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parameter values. After installation, some tunable parameters may no longer be at the default or recommended values. For information about the effects of installation on tun- able values, consult the documentation for the kernel software being installed. For information about optional kernel software that was factory installed on your system, see at AUTHOR
was developed by HP. SEE ALSO
kctune(1M), sam(1M), gettune(2), settune(2), fcntl(2), lockf(2). Tunable Kernel Parameters nflocks(5)
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maxfiles(5) File Formats Manual maxfiles(5) NAME
maxfiles - initial (soft) maximum number of file descriptors per process VALUES
Failsafe Default The default value is computed at runtime and depends on the amount of physical memory on the system. For small memory systems (less than 1GB), the default is 512. For systems with more than 1GB of memory, the default is 2048, or 2K. Allowed values The minimum value is 32. The maximum value is 1048576, or 1M. The value is further constrained in that it must be equal to or less than the hard limit, Specify a positive integer value. Recommended values At runtime, a warning will be issued if the tunable is set to a value greater than 409600, or 400K. This is beyond the tested limit. At runtime, a warning will be issued if the value is not a multiple of the file descriptor chunk (multiple of 8) size. This is not a seri- ous warning, just an information message for the administrator. DESCRIPTION
specifies the initial default number of file descriptors a process is allowed to have for open files at any given time. It is possible for a process to increase its soft limit and therefore open more than files. Nonsuperuser processes can increase their soft limit using or until they reach the hard limit, Who Is Expected to Change This Tunable? This value of this tunable rarely needs to be modified. However, this tunable may need to be modified on systems that will run applica- tions using large numbers of file descriptors, or on systems where memory consumption needs to be reduced. Restrictions on Changing This tunable is static. To have changes to the value of this tunable take effect, a system reboot is required. When Should the Value of This Tunable Be Raised? This tunable may need to be raised on systems that will run applications using large numbers of file descriptors if the applications do not already increase their process soft limit, for example using What are the Side Effects of Raising the Value? The initial process memory footprint grows due to a larger per process file table. When Should the Value of This Tunable Be Lowered? The value should be lowered to limit the number of initial file descriptors per process on a system to reduce memory consumption. What are the Side Effects of Lowering the Value? The initial process memory footprint shrinks due to a smaller per process file table. What Other Tunable Values Should Be Changed at the Same Time? The value assigned to must be less than or equal to the value of Kernel checks during tunable setting ensure this. WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its meaning changed in future releases of HP-UX. Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parameter values. After installation, some tunable parameters may no longer be at the default or recommended values. For information about the effects of installation on tun- able values, consult the documentation for the kernel software being installed. For information about optional kernel software that was factory installed on your system, see at AUTHOR
was developed by HP. SEE ALSO
kctune(1M), sam(1M), gettune(2), settune(2), ulimit(2), setrlimit(2), maxfiles_lim(5). Tunable Kernel Parameters maxfiles(5)