INFODOC ID: 11915 STATUS: Issued 
SYNOPSIS: List of tunable parameters for Solaris 2.3 through 2.6 
DETAIL DESCRIPTION: 

The following table lists the general kernel parameters that can be tuned.

Parameter       Description
---------       -----------

dump_cnt        Size of the dump

autoup          Used in struct var for dynamic configuration of the 
	        age that a delayed-write buffer must be,in seconds, 
	        before bdflush will write it out (default = 60)

bufhwm          Used in struct var for v_bufhwm; it's the high water 
	        mark for buffer cache memory usage, in Kbytes 
	        (default = 2% of physical memory).

maxusers        Maximum number of users 
	        The default is number of Megabytes in physical memory minus 2.

max_nprocs      Maximum number of processes (default = 10 + 16 * maxusers).

maxuprc         The maximum number of user processes.
	 	(default = max_nprocs - 5)

rstchown        POSIX_CHOWN_RESTRICTED is enabled (default = 1).

ngroups_max     Maximum number of supplementary groups per user 
	 	(default = 32).

rlim_fd_cur     Maximum number of open file descriptors per process
	 	sysem wide (default = 64, max = 1024) also seelimit(1).


Streams Parameters:

nautopush       Number of entries in the autopush free list, 
	 the high water mark for Streams administrative 
	 devices (sads). One autopush entry is needed for each 
	 entry in the /etc/iu.ap file and any others that may 
	 be configured by using the autopush command directly,
	 or by openingthe sad device and using the SAD_SAP
	 ioctl(). If you run out of autopush entries, the ioctl()
	 will return -1 and set errno to ENOSR (out of streams
	 resources).

sadcnt    Number allowed of concurrent opens of both
	 /dev/sad/user and /dev/sad/admin (default 16).
	 Once all are in use, open() will return -1 and 
	 set errno to ENXIO (No such device or address).


Psuedo Devices: (Needs reboot -r to take effect)

npty     Number of 4.X pseudo-ttys configured (default = 48).
	 The device entries are /dev/pty*

pt_cnt   Number of 5.X pseudo-ttys configured (default = 48).
	 (keep below 3000)
	 The device entries are /dev/pts/*



Paging Parameters:

physmem  Sets the number of pages usable in physical memory.
	 Only use this for testing, it reduces the size of usable memory.

minfree  Memory threshold which determines when to start swapping
	 processes, when free memory falls to this level swapping
	 begins (default:
	 2.5.1 and later : desfree / 2
	 2.5 : desfree / 2 at most 100k bytes (sun4d 200k bytes)
	 2.4 : 4d = 50 pages, all others 25 pages
	 2.3 : physmem / 64 ).

desfree  This is the desired free level, this determines when
	 paging is abandoned for swapping. When free memory stays 
	 below this level for 30 seconds, swapping kicks in
	 (default:
	 2.5.1 and later : lotsfree / 2
	 2.5 : physmem / 64 at most 200k bytes (sun4d 400k bytes)
	 2.4 : 4d = 100 pages, all others 50 pages, 
	 2.3 : physmem / 32 ).

lotsfree Memory threshold which determines when to start paging.
	 When free memory falls below this level paging begins
	 (default:
	 2.5.1 and later : physmem / 64 or at least 512k bytes worth of pages
	 2.5 : physmem / 32 at most 512k bytes (sun4d 1024k bytes)
	 2.4 : 4d = 256 pages all others 128 pages
	 2.3 : physmem / 16 ).

fastscan The number of pages scanned per second when free memory
	 is zero, the scan rate increases as free memory falls
	 from lotsfree to zero, reaching fastscan (default:
	 2.5 and later : physmem / 2 with 64Mb of memory being max
	 2.4 : physmem / 4 with 64Mb of memory being max
	 2.3 : physmem / 2 ).

slowscan The number of pages scanned per second when free memory
	 is equal to lotsfree, also see fastscan (default:
	 2.5 and later : fastscan / 10 but not to exceed 100
	 2.4 : is fixed at 100, 
	 2.3 : fastscan / 10 ).

handspreadpages The distance between the fronthand and backhand in
	 the clock algorithm. The larger the number the longer an
	 idle page can stay in memory (default:
	 2.5 and later : fastscan
	 2.4 : physmem / 4
	 2.3 : physmem / 2 ).

maxpgio  The maximum number of page-out I/O operations per second.
	 This acts as a throttle for the page deamon to prevent
	 page thrashing ((DISKRPM * 2) /3 ).

t_gpgslo 2.1 through 2.3, Used to set the threshold on when to 
	 swap out processes (default 25 pages ).



File System Parameters:

ufs_ninode      Maximum number of inodes.
	 	(default = max_nprocs + 16 + maxusers + 64)

ndquot   Number of disk quota structures.
	 (default = (maxusers * NMOUNT / 4) + max_nprocs)

ncsize   Number of dnlc entries.
	 (default = max_procs + 16 + maxusers + 64);
	 dnlc is the directory-name lookup cache


TCP/IP Parameters:

arptab_size     Size of arp table

ipcnt           Size of ip_pcb

ipprovcnt       Size of provider

loopcnt         Size of loop_pcb

ntcp            Number of tcp devices, tcp_dev

nudp            Number of udp devices, udp_dev


APPLIES TO: Hardware, Operating Systems/Solaris/Solaris 2.x, AFO Vertical Team 
Docs, AFO Vertical Team Docs/Kernel