Installation guide

physical memory. If this total amount is greater than the size of physical
memory, the swap space must be large enough to hold the modified virtual
pages that do not fit into your physical memory. If your system’s workload
is complex and you are unable to estimate the appropriate amount of swap
space by using this method, you should first use the default amount of
swap space and adjust the swap space as needed.
You should always monitor your system’s use of swap space. If the system
issues messages that indicate that swap space is almost depleted, you can
use the swapon command to allocate additional swap space. If you use the
immediate mode, swap space depletion prevents you from creating
additional modifiable virtual address space. If you use the deferred mode,
swap space depletion may result in one or more processes being
involuntarily terminated.
7.1.2.3 Selecting the Swap Space Allocation Method
To determine which swap space allocation method is being used, check for
the existence of a soft link named /sbin/swapdefault, which points to
the primary swap partition. If the /sbin/swapdefault file exists, the
system uses the immediate method of swap space allocation. To enable the
deferred method, rename or delete this soft link.
You may receive the following informational messages when you remove
the /sbin/swapdefault file and when you boot a system that is using the
deferred method:
vm_swap_init: warning sbin/swapdefault swap device not found
vm_swap_init: in swap over-commitment mode
If the /sbin/swapdefault file does not exist and you want to enable the
immediate method of swap allocation, become the root user and create the
file by using the following command syntax:
ln −s ../dev/rzxy /sbin/swapdefault
The
x variable specifies the device number for the device that holds the
primary swap partition, and the
y variable specifies the swap partition.
Usually, the swap device number is the same as the boot device number,
and the primary swap partition is partition b.
You must reboot the system for the new method to take effect.
7.1.3 UNIX File System Structure
This section discusses the UNIX File System (UFS). For information on the
Advanced File System (AdvFS) structure, refer to AdvFS Administration.
7–6 Administering the UNIX File System