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Oracle Solaris Tunable Parameters Reference Manual     Oracle Solaris 11 Express 11/10
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Document Information

Preface

1.  Overview of Oracle Solaris System Tuning

2.  Oracle Solaris Kernel Tunable Parameters

Where to Find Tunable Parameter Information

General Kernel and Memory Parameters

physmem

zfs_arc_min

zfs_arc_max

default_stksize

lwp_default_stksize

logevent_max_q_sz

segkpsize

noexec_user_stack

fsflush and Related Parameters

fsflush

tune_t_fsflushr

autoup

dopageflush

doiflush

Process-Sizing Parameters

maxusers

reserved_procs

pidmax

max_nprocs

maxuprc

ngroups_max

Paging-Related Parameters

lotsfree

desfree

minfree

throttlefree

pageout_reserve

pages_pp_maximum

tune_t_minarmem

fastscan

slowscan

min_percent_cpu

handspreadpages

pages_before_pager

maxpgio

Swapping-Related Parameters

swapfs_reserve

swapfs_minfree

Kernel Memory Allocator

kmem_flags

kmem_stackinfo

General Driver Parameters

moddebug

ddi_msix_alloc_limit

Network Driver Parameters

igb Parameters

mr_enable

intr_force

ixgbe Parameters

tx_queue_number

rx_queue_number

intr_throttling

rx_limit_per_intr

tx_ring_size

rx_ring_size

tx_copy_threshold

rx_copy_threshold

General I/O Parameters

maxphys

rlim_fd_max

rlim_fd_cur

General File System Parameters

ncsize

rstchown

dnlc_dir_enable

dnlc_dir_min_size

dnlc_dir_max_size

segmap_percent

UFS Parameters

bufhwm and bufhwm_pct

ndquot

ufs_ninode

ufs_WRITES

ufs_LW and ufs_HW

freebehind

smallfile

TMPFS Parameters

tmpfs:tmpfs_maxkmem

tmpfs:tmpfs_minfree

Pseudo Terminals

pt_cnt

pt_pctofmem

pt_max_pty

STREAMS Parameters

nstrpush

strmsgsz

strctlsz

System V Message Queues

System V Semaphores

System V Shared Memory

segspt_minfree

Scheduling

rechoose_interval

Timers

hires_tick

timer_max

sun4u or sun4v Specific Parameters

consistent_coloring

tsb_alloc_hiwater_factor

default_tsb_size

enable_tsb_rss_sizing

tsb_rss_factor

Locality Group Parameters

lpg_alloc_prefer

lgrp_mem_default_policy

lgrp_mem_pset_aware

3.  NFS Tunable Parameters

4.  Internet Protocol Suite Tunable Parameters

5.  Network Cache and Accelerator Tunable Parameters

6.  System Facility Parameters

A.  Tunable Parameters Change History

B.  Revision History for This Manual

Index

Swapping-Related Parameters

Swapping in the Solaris OS is accomplished by the swapfs pseudo file system. The combination of space on swap devices and physical memory is treated as the pool of space available to support the system for maintaining backing store for anonymous memory. The system attempts to allocate space from disk devices first, and then uses physical memory as backing store. When swapfs is forced to use system memory for backing store, limits are enforced to ensure that the system does not deadlock because of excessive consumption by swapfs.

swapfs_reserve

Description

Defines the amount of system memory that is reserved for use by system (UID = 0) processes.

Data Type

Unsigned long

Default

The smaller of 4 MB and 1/16th of physical memory

Range

The minimum value is 4 MB or 1/16th of physical memory, whichever is smaller, expressed as pages using the page size returned by getpagesize.

The maximum value is the number of physical memory pages. The maximum value should be no more than 10 percent of physical memory. The system does not enforce this range, other than that described in the Validation section.

Units

Pages

Dynamic?

No

Validation

None

When to Change

Generally not necessary. Only change when recommended by a software provider, or when system processes are terminating because of an inability to obtain swap space. A much better solution is to add physical memory or additional swap devices to the system.

Commitment Level

Unstable

swapfs_minfree

Description

Defines the desired amount of physical memory to be kept free for the rest of the system. Attempts to reserve memory for use as swap space by any process that causes the system's perception of available memory to fall below this value are rejected. Pages reserved in this manner can only be used for locked-down allocations by the kernel or by user-level processes.

Data Type

Unsigned long

Default

The larger of 2 MB and 1/8th of physical memory

Range

1 to amount of physical memory

Units

Pages

Dynamic?

No

Validation

None

When to Change

When processes are failing because of an inability to obtain swap space, yet the system has memory available.

Commitment Level

Unstable