Tunable Kernel Parameters

Table of Tunable Kernel Parameters
Appendix A
74
Memory Paging swapmem_on Enable or disable pseudo-swap allocation. This allows
systems with large installed memory to allocate memory
space as well as disk swap space for virtual memory use
instead of restricting availability to defined disk swap
area. Manpage: swapmem_on (5).
Memory Paging swchunk Amount of space allocated for each chunk of swap area.
Chunks are allocated from device to device by the kernel.
Changing this parameter requires extensive knowledge of
system internals. Without such knowledge, do not change
this parameter from the normal default value. Manpage:
swchunk (5).
Spinlock Pool sysv_hash_locks System V interprocess communication spinlock pool.
Manpage: sysv_hash_locks (5).
Miscellaneous:
Network
tcphashsz TCP hash table size, in bytes. Manpage: tcphashsz (5).
ProcessMgmt:
CPU
timeslice Maximum time a process can use the CPU until it is made
available to the next process having the same process
execution priority. This feature also prevents runaway
processes from causing system lock-up. Manpage: timeslice
(5).
Miscellaneous:
Clock
timezone The offset between the local time zone and Coordinated
Universal Time (UTC), often called Greenwich Mean Time
or GMT. Manpage: timezone (5).
Miscellaneous:
Memory
unlockable_mem Amount of system memory to be reserved for system
overhead and virtual memory management, that cannot
be locked by user processes. Manpage: unlockable_mem
(5).
Spinlock Pool vnode_cd_hash_locks Vnode clean/dirty spinlock pool. NO MANPAGE.
Spinlock Pool vnode_hash_locks Vnode spinlock pool. NO MANPAGE.
Memory Paging:
Size
vps_ceiling Maximum system-selected page size (in KB) if the user
does not specify a page size. Manpage: vps_ceiling (5).
Memory Paging:
Size
vps_chatr_ceiling Maximum page size a user can specify with the chatr
command in a program. Manpage: vps_chatr_ceiling (5).
Memory Paging:
Size
vps_pagesize Minimum user page size (in KB) if no page size is specified
using chatr. Manpage: vps_pagesize (5).
File System:
Journaled
vxfs_max_ra_kbytes Maximum amount of read-ahead data, in KB, that the
kernel may have outstanding for a single VxFS file
system. Manpage: vxfs_max_ra_kbytes (5).
Table A-1 Tunable Kernel Parameters in Alphabetic Order (Continued)
Category Tunable Description