maxfiles(5) [hpux man page]
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)
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maxfiles_lim(5) File Formats Manual maxfiles_lim(5) NAME
maxfiles_lim - hard maximum number of file descriptors per process VALUES
Failsafe Default Allowed values The minimum value allowed is 32. The maximum value allowed is 1048576, or 1M. The value is further constrained in that it must be equal or greater than the soft 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 system hard limit for the number of file descriptors that a process is allowed to have for open files at any given time. It is possible for a nonsuperuser process to increase its soft limit up to this hard limit. Who Is Expected to Change This Tunable? Anyone expecting to run applications using large numbers of file descriptors. Restrictions on Changing The tunable is dynamic (tuning will take effect immediately on the running system). Dynamic changes affect all existing processes in the system except: o Processes that have more file descriptors allocated than allowed by the new limit, o Processes that have specifically set their limits through a call to or When Should the Value of This Tunable Be Raised? The tunable should be increased when large numbers of file descriptors are expected to be open by several processes. What are the Side Effects of Raising the Value? There is no immediate effect of raising the value of However, doing so allows any process to allocate more file descriptors, potentially consuming more system memory. When Should the Value of This Tunable Be Lowered? The value should be lowered to limit the number of open file descriptors per process on a system and reduce system memory consumption. What are the Side Effects of Lowering the Value? Lowering the value of bounds memory consumption due to file descriptors for processes that are not already over the new limit. 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 these restrictions. WARNINGS
For values greater than 65535, compatibility for the obsolescent will be affected. For correct operation, all applications must use instead of If the system still has applications using setting to 65535 or less will maintain compatibility, unless the process being queried has used to change its maximum limit of open files to a value greater than 65535. 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), setrlimit(2), gettune(2), settune(2), pstat(2), ulimit(2), maxfiles(5). Tunable Kernel Parameters maxfiles_lim(5)