remote_nfs_swap(5)remote_nfs_swap(5)NAMEremote_nfs_swap - enable swapping across NFS
VALUES
Default
Allowed values
DESCRIPTION
This tunable controls adding a NFS filesystem for use as swap. If is
set to only local filesystems and devices can be used for swap. If it
is set to both local and networked file systems can be used for swap.
Historically, this tunable was used in NFS clusters that are no longer
supported, but this capability has not yet been removed.
Who Is Expected to Change This Tunable?
Anyone.
Restrictions on Changing
Changes to this tunable take effect on the next boot.
When Should the Tunable Be Turned On?
Almost never. As previously mentioned, this tunable was designed for
systems which are not in use today. Only systems with extremely robust
NFS capabilities should even consider using NFS for swap.
What Are the Side Effects of Turning the Tunable On?
If the value is set to and a NFS partition is added as swap, then some
kernel memory will be set aside for NFS transactions to the swap file
system. The kernel will then use the NFS swap partition just the same
as a local file system. If the NFS capabilities of the system are not
robust, this could lead to extremely long swap times (both swap in and
swap out), and possibly a loss of memory because all the reserved mem‐
ory and more could be used by NFS (just when memory pressure is high)
causing the need for swap.
When Should the Tunable Be Turned Off?
Unless you are positive that the NFS system can handle the load of
being used as swap, and does not have a local file system or disk drive
to spare, this tunable should be set to
What Are the Side Effects of Turning the Tunable Off?
Any previously defined NFS swap filesystems will no longer be allowed.
Kernel memory will not be reserved for NFS transactions due to swap.
What Other Tunables Should Be Changed at the Same Time?
None.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parame‐
ter 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 val‐
ues. For information about the effects of installation on tunable val‐
ues, 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.
Tunable Kernel Parameters remote_nfs_swap(5)