NAME
nswapfs — maximum number of file systems that can be enabled for swap
VALUES
Allowed values
Minimum: 0 file systems
Maximum: 1024 files systems
DESCRIPTION
File system swap devices are managed in a table for easier indexing
in the kernel.
nswapfs
sets the kernel variable responsible for the upper limit on this
table, and thus the upper limit to file systems which can be used for swap.
Who is Expected to Change This Tunable?
Anyone.
Restrictions on Changing
Changes to this tunable take effect at the next reboot.
When Should the Value of This Tunable Be Raised?
If another file system swap is added to the system which would increase
the number above
nswapfs,
then
swapon()
returns
ENOENT
to the caller
(see the
swapon(2)
manpage).
What Are the Side Effects of Raising the Value?
More file systems for swap can be added to the system, and the
kernel will need a little more memory for the table.
A small performance side effect of the kernel having to scan
more file systems to check for a duplicate during swapon is also true,
but realistically negligible.
When Should the Value of This Tunable Be Lowered?
Only if you are sure the system will never go over a certain
number of swap file systems, and you wish to lower this tunable
to save a small amount of kernel memory and kernel performance
during swapon operations.
What Are the Side Effects of Lowering the Value?
No side effects other than the primary and presumably desired
new limitation on the number of swap file systems.
What Other Tunable Values Should Be Changed at the Same Time?
None.
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 tunable values, consult the documentation
for the kernel software being installed.
For information about optional kernel software that was
factory installed on your system, see
HP-UX Release Notes
at
http://docs.hp.com.
AUTHOR
nswapfs
was developed by HP.
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