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)