Memory File System (MemFS) 1.0 for HP-UX 11i v3

Installing, Configuring, Tuning, and Removing HP-UX Memory File System
Configuring Memory File System
Chapter 216
Configuring Memory File System
A MemFS instance can be created either through a mount(1m) command, or automatically
through an entry in the /etc/fstab file or by calling mount(2m) system call.
Following is the syntax for mounting an MemFS instance using the mount(1) command:
# /usr/sbin/mount -F memfs [-eQV] [-o size=<size>, ninode=<ninode>, remount]\
directory
For example, to create an MemFS instance of size 100MB with 10000 inodes and mounting it
on /memfs:
# /usr/sbin/mount -F memfs -o size=100MB,ninode=10000 /memfs
For example, to automatically mount after system reboot, a MemFS instance of size 50MB
with 1000 inodes on a mount point, /memfs add the following entry to /etc/fstab file:
memfs /memfs memfs size=50MB, ninode=1000 0 0
The optional size argument can be used to specify the size of a MemFS instance. Append to
size, kb or KB to indicate the value is in kilobytes, mb or MB to indicate megabytes, or gb or
GB to indicate gigabytes. If size is not specified or is specified as 0, the size of the file system
is not limited and can grow based on the available swap space for MemFS. After mounting a
MemFS file system, the mounted instance can be listed using the bdf(1)/df(1) command. For
example, the above mounted instance will be listed with bdf command, as shown below:
Filesystem kbytes used avail %used Mounted on
memfs 102400 0 102400 0% /memfs
The swap space is shared by all the MemFS instances in a system and other process running
on the system will also consume certain amount of swap space. Because of this, the size
argument does not guarantee that the specified size is available for use by a MemFS instance
always. If the size option is specified, it just ensures that the file system does not grow beyond
the specified value. There can be situations where % used will be much less than 100% and no
space left on the swap device to write data. In such situations MemFS displays available
space as 0. If size option is not specified or specified as zero, the size of a mounted instance
will be the summation of the available free swap for MemFS and the amount of swap space
consumed by that particular instance. Depending on the swap usage, the size of a mounted
MemFS instance can be varying over time. However, if size option is specified the size of the
mounted instance is fixed to the specified value and does not change over time.
The optional ninode argument can be used to specify the maximum number of files that can
be created with in a particular instance. If ninode is 0 or the option is not specified the
number of files is not restricted, though it is limited by the available memory for MemFS.