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

Installing, Configuring, Tuning, and Removing HP-UX Memory File System
Tuning Memory File System
Chapter 2 19
3. A constant value: A positive whole number that represents number of bytes of kernel
memory, optionally followed by a multiplier suffix, where K=1000, KB=1024, M=1000000,
MB=(1024*1024), and GB=(1024*1024*1024). For example, a constant value could be
500K.
Example:
kctune -s memfs_metamax=100MB
If MemFS utilizes all the memory specified by this tunable, mounting of new MemFS file
systems and creation of new files on them will fail and following message will be displayed on
console:
memfs: metadata exceeds memfs_metamax
This tunable can be modified dynamically. If the new limit specified is less than the memory
in use by MemFS metadata (for example 20480 bytes), following warning will be displayed on
console:
Warning: The specified value of tunable memfs_metamax is less than the amount
of memory currently in use by MemFS, 20480 bytes.
memfs_swapmax_pct
The memfs_swapmax_pct tunable defines the maximum amount of system swap space that
can be used by all MemFS instances in a system as percentage of total system swap
configured in a system. The tunable does not reserve or assure the swap space of specified
size; it just assures that the swap space usage by MemFS does not grow beyond the specified
size. The value of this tunable can be as low as 0% of system swap or as high as 80% of system
swap. The default value is 50% of system swap.
Tunable values can be specified as follows:
1. Default
Example:
kctune -s memfs_swapmax_pct=Default
2. A percentage of total swap space; a positive whole number (0-80)
Example:
kctune -s memfs_swapmax_pct=60
Data in MemFS files share the system swap device used by others. Therefore, it is important
to define a value for this tunable that balances MemFS swap usage and usage for the rest of
the system. If the value is too low, then applications can not issue those writes which results
in new block allocations to write data to MemFS files. Tuning this tunable too high and if