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Oracle Solaris Tunable Parameters Reference Manual     Oracle Solaris 10 1/13 Information Library
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Document Information

Preface

1.  Overview of Oracle Solaris System Tuning

2.  Oracle Solaris Kernel Tunable Parameters

3.  Oracle Solaris ZFS Tunable Parameters

4.  NFS Tunable Parameters

5.  Internet Protocol Suite Tunable Parameters

6.  System Facility Parameters

A.  Tunable Parameters Change History

Kernel Parameters

General Kernel and Memory Parameters (Oracle Solaris 10)

zfs_arc_min

zfs_arc_max

noexec_user_stack (Solaris 10 Releases)

lwp_default_stksize (Solaris 10 Releases)

Paging-Related Parameters

fastscan

Process-Sizing Tunables

ngroups_max (Solaris 10 Releases

max_nprocs (Solaris 10 Releases)

UFS Parameter

ufs_delete_hiwat

General Driver Parameter

ddi_msix_alloc_limit

General I/O Tunable Parameters

maxphys (Solaris 10 Releases)

fsflush and Related Parameters

dopageflush (Solaris 10 Releases)

Paging-Related Tunable Parameters

maxpgio (Solaris 10 Releases)

General File System Parameters

ncsize (Solaris 10 Release)

TMPFS Parameters

tmpfs:tmpfs_maxkmem (Solaris 10 Releases)

SPARC System Specific Parameters (Solaris 10 Releases)

default_tsb_size (Solaris 10 Releases)

enable_tsb_rss_sizing (Solaris 10 Releases)

tsb_rss_factor (Solaris 10 Releases)

NFS Tunable Parameters

nfs:nfs3_nra (Solaris 10 Releases)

TCP/IP Tunable Parameters

ip_forward_src_routed and ip6_forward_src_routed (Solaris 10 Releases)

ip_multidata_outbound (Solaris 10 Releases)

ip_squeue_fanout (Solaris 10 11/06 Release)

ip_squeue_worker_wait (Solaris 10 11/06 Release)

ip_soft_rings_cnt (Solaris 10 11/06 Release)

ip_squeue_write (Solaris 10 Releases)

tcp_local_dack_interval (Solaris 10 Releases)

[tcp,sctp,udp]_smallest_anon_port and [tcp,sctp,udp]_largest_anon_port

tcp_naglim_def (Solaris 10 Releases)

udp_do_checksum (Solaris 10 Releases)

Parameters That Are Obsolete or Have Been Removed (Oracle Solaris 10)

rstchown

System V Message Queue Parameters

msgsys:msginfo_msgmni

msgsys:msginfo_msgtql

msgsys:msginfo_msgmnb

msgsys:msginfo_msgssz

msgsys:msginfo_msgmap

msgsys:msginfo_msgseg

msgsys:msginfo_msgmax

System V Semaphore Parameters

semsys:seminfo_semmni

semsys:seminfo_semmsl

semsys:seminfo_semopm

semsys:seminfo_semmns

semsys:seminfo_semmnu

semsys:seminfo_semume

semsys:seminfo_semvmx

semsys:seminfo_semaem

System V Shared Memory Parameters

shmsys:shminfo_shmmni

shmsys:shminfo_shmmax

B.  Revision History for This Manual

Index

Parameters That Are Obsolete or Have Been Removed (Oracle Solaris 10)

The following section describes parameters that are obsolete or have been removed from more recent Oracle Solaris releases.

rstchown

This parameter is obsolete starting in the Oracle Solaris 10 8/11 release.

Description

Indicates whether the POSIX semantics for the chown system call are in effect. POSIX semantics are as follows:

  • A process cannot change the owner of a file, unless it is running with UID 0.

  • A process cannot change the group ownership of a file to a group in which it is not currently a member, unless it is running as UID 0.

For more information, see chown(2).

Data Type

Signed integer

Default

1, indicating that POSIX semantics are used

Range

0 = POSIX semantics not in force or 1 = POSIX semantics used

Units

Toggle (on/off)

Dynamic?

Yes

Validation

None

When to Change

When POSIX semantics are not wanted. Note that turning off POSIX semantics opens the potential for various security holes. Doing so also opens the possibility of a user changing ownership of a file to another user and being unable to retrieve the file without intervention from the user or the system administrator.

Commitment Level

Obsolete

System V Message Queue Parameters

msgsys:msginfo_msgmni

Obsolete in the Solaris 10 release.

Description

Maximum number of message queues that can be created.

Data Type

Signed integer

Default

50

Range

0 to MAXINT

Dynamic?

No. Loaded into msgmni field of msginfo structure.

Validation

None

When to Change

When msgget(2) calls return with an error of ENOSPC or at the recommendation of a software vendor.

Commitment Level

Unstable

msgsys:msginfo_msgtql

Obsolete in the Solaris 10 release.

Description

Maximum number of messages that can be created. If a msgsnd call attempts to exceed this limit, the request is deferred until a message header is available. Or, if the request has set the IPC_NOWAIT flag, the request fails with the error EAGAIN.

Data Type

Signed integer

Default

40

Range

0 to MAXINT

Dynamic?

No. Loaded into msgtql field of msginfo structure.

Validation

None

When to Change

When msgsnd() calls block or return with error of EGAIN, or at the recommendation of a software vendor.

Commitment Level

Unstable

msgsys:msginfo_msgmnb

Obsolete in the Solaris 10 release.

Description

Maximum number of bytes that can be on any one message queue.

Data Type

Unsigned long

Default

4096

Range

0 to amount of physical memory

Units

Bytes

Dynamic?

No. Loaded into msgmnb field of msginfo structure.

Validation

None

When to Change

When msgsnd() calls block or return with an error of EGAIN, or at the recommendation of a software vendor.

Commitment Level

Unstable

msgsys:msginfo_msgssz

Removed in the Solaris 10 release.

Description

Specifies size of chunks system uses to manage space for message buffers.

Data Type

Signed integer

Default

40

Range

0 to MAXINT

Dynamic?

No. Loaded into msgtql field of msginfostructure.

Validation

The space consumed by the maximum number of data structures that would be created to support the messages and queues is compared to 25% of the available kernel memory at the time the module is loaded. If the number is too big, the message queue module refuses to load and the facility is unavailable. This computation does include the space that might be consumed by the messages. This situation occurs only when the module is first loaded.

When to Change

When the default value is not enough. Generally changed at the recommendation of software vendors.

Commitment Level

Obsolete

msgsys:msginfo_msgmap

Removed in the Solaris 10 release.

Description

Number of messages the system supports.

Data Type

Signed integer

Default

100

Range

0 to MAXINT

Dynamic?

No

Validation

The space consumed by the maximum number of data structures that would be created to support the messages and queues is compared to 25% of the available kernel memory at the time the module is loaded. If the number is too big, the message queue module refuses to load and the facility is unavailable. This computation does include the space that might be consumed by the messages. This situation occurs only when the module is first loaded.

When to Change

When the default value is not enough. Generally changed at the recommendation of software vendors.

Commitment Level

Obsolete

msgsys:msginfo_msgseg

Removed in the Solaris 10 release.

Description

Number of msginfo_msgssz segments the system uses as a pool for available message memory. Total memory available for messages is msginfo_msgseg * msginfo_msgssz.

Data Type

Signed short

Default

1024

Range

0 to 32,767

Dynamic?

No

Validation

The space consumed by the maximum number of data structures that would be created to support the messages and queues is compared to 25% of the available kernel memory at the time the module is loaded. If the number is too big, the message queue module refuses to load and the facility is unavailable. This computation does not include the space that might be consumed by the messages. This situation occurs only when the module is first loaded.

When to Change

When the default value is not enough. Generally changed at the recommendation of software vendors.

Commitment Level

Obsolete

msgsys:msginfo_msgmax

Removed in the Solaris 10 release.

Description

Maximum size of System V message.

Data Type

Unsigned long

Default

2048

Range

0 to amount of physical memory

Units

Bytes

Dynamic?

No. Loaded into msgmax field of msginfo structure.

Validation

None

When to Change

When msgsnd(2) calls return with error of EINVAL or at the recommendation of a software vendor.

Commitment Level

Unstable

System V Semaphore Parameters

semsys:seminfo_semmni

Obsolete in the Solaris 10 release.

Description

Specifies the maximum number of semaphore identifiers.

Data Type

Signed integer

Default

10

Range

1 to 65,535

Dynamic?

No

Validation

Compared to SEMA_INDEX_MAX (currently 65,535) and reset to that value if larger. A warning message is written to the console, messages file, or both.

When to Change

When the default number of sets is not enough. Generally changed at the recommendation of software vendors. No error messages are displayed when an attempt is made to create more sets than are currently configured. Instead, the application receives a return code of ENOSPC from a semget call.

For more information, see semget(2).

Commitment Level

Unstable

semsys:seminfo_semmsl

Obsolete in the Solaris 10 release.

Description

Specifies the maximum number of System V semaphores per semaphore identifier.

Data Type

Signed integer

Default

25

Range

1 to MAXINT

Dynamic?

No

Validation

The amount of space that could possibly be consumed by the semaphores and their supporting data structures is compared to 25 percent of the kernel memory available at the time the module is first loaded. If the memory threshold is exceeded, the module refuses to load and the semaphore facility is not available.

When to Change

When the default value is not enough. Generally changed at the recommendation of software vendors. No error messages are displayed when an attempt is made to create more semaphores in a set than are currently configured. The application sees a return code of EINVAL from a semget(2) call.

Commitment Level

Unstable

semsys:seminfo_semopm

Obsolete in the Solaris 10 release.

Description

Specifies the maximum number of System V semaphore operations per semop call. This parameter refers to the number of sembufs in the sops array that is provided to the semop() system call. For more information, see semop(2).

Data Type

Signed integer

Default

10

Range

1 to MAXINT

Dynamic?

No

Validation

The amount of space that could possibly be consumed by the semaphores and their supporting data structures is compared to 25 percent of the kernel memory available at the time the module is first loaded. If the memory threshold is exceeded, the module refuses to load and the semaphore facility is not available.

When to Change

When the default value is not enough. Generally changed at the recommendation of software vendors. No error messages are displayed when an attempt is made to perform more semaphore operations in a single semop call than are currently allowed. Instead, the application receives a return code of E2BIG from a semop() call.

Commitment Level

Unstable

semsys:seminfo_semmns

Removed in the Solaris 10 release.

Description

Maximum number of System V semaphores on the system.

Data Type

Signed integer

Default

60

Range

1 to MAXINT

Dynamic?

No

Validation

The amount of space that could possibly be consumed by the semaphores and their supporting data structures is compared to 25% of the kernel memory available at the time the module is first loaded. If the memory threshold is exceeded, the module refuses to load and the semaphore facility is not available.

When to Change

When the default number of semaphores is not enough. Generally changed at the recommendation of software vendors. No error messages are displayed when an attempt is made to create more semaphores than are currently configured. The application sees a return code of ENOSPC from a semget(2) call.

Commitment Level

Unstable

semsys:seminfo_semmnu

Removed in the Solaris 10 release.

Description

Total number of undo structures supported by the System V semaphore system.

Data Type

Signed integer

Default

30

Range

1 to MAXINT

Dynamic?

No

Validation

The amount of space that could possibly be consumed by the semaphores and their supporting data structures is compared to 25% of the kernel memory available at the time the module is first loaded. If the memory threshold is exceeded, the module refuses to load and the semaphore facility is not available.

When to Change

When the default value is not enough. Generally changed at the recommendation of software vendors. No error message is displayed when an attempt is made to perform more undo operations than are currently configured. The application sees a return value of ENOSPC from a semop(2) call when the system runs out of undo structures.

Commitment Level

Unstable

semsys:seminfo_semume

Description

Removed in the Solaris 10 release.

Maximum number of System V semaphore undo structures that can be used by any one process.

Data Type

Signed integer

Default

10

Range

1 to MAXINT

Dynamic?

No

Validation

The amount of space that could possibly be consumed by the semaphores and their supporting data structures is compared to 25% of the kernel memory available at the time the module is first loaded. If the memory threshold is exceeded, the module refuses to load and the semaphore facility is not available.

When to Change

When the default value is not enough. Generally changed at the recommendation of software vendors. No error messages are displayed when an attempt is made to perform more undo operations than are currently configured. The application sees a return code of EINVAL from a semop(2) call.

Commitment Level

Unstable

semsys:seminfo_semvmx

Removed in the Solaris 10 release.

Description

Maximum value a semaphore can be set to.

Data Type

Unsigned short

Default

32,767

Range

1 to 65,535

Dynamic?

No

Validation

None

When to Change

When the default value is not enough. Generally changed at the recommendation of software vendors. No error messages are displayed when the maximum value is exceeded. The application sees a return code of ERANGE from a semop(2) call.

Commitment Level

Unstable

semsys:seminfo_semaem

Removed in the Solaris 10 release.

Description

Maximum value that a semaphore's value in an undo structure can be set to.

Data Type

Unsigned short

Default

16,384

Range

1 to 65,535

Dynamic?

No

Validation

None

When to Change

When the default value is not enough. Generally changed at the recommendation of software vendors. No error messages are displayed when an attempt is made to perform more undo operations than are currently configured. The application sees a return code of EINVAL from a semop(2) call.

Commitment Level

Unstable

System V Shared Memory Parameters

shmsys:shminfo_shmmni

Obsolete in the Solaris 10 release.

Description

System wide limit on number of shared memory segments that can be created.

Data Type

Signed integer

Default

100

Range

0 to MAXINT

Dynamic?

No. Loaded into shmmni field of shminfo structure.

Validation

The amount of space consumed by the maximum possible number of data structures to support System V shared memory is checked against 25% of the currently available kernel memory at the time the module is loaded. If the memory consumed is too large, the attempt to load the module fails.

When to Change

When the system limits are too low. Generally changed on the recommendation of software vendors.

Commitment Level

Unstable

shmsys:shminfo_shmmax

Obsolete in the Solaris 10 release.

Description

Maximum size of system V shared memory segment that can be created. This parameter is an upper limit that is checked before the application sees if it actually has the physical resources to create the requested memory segment.

Attempts to create a shared memory section whose size is zero or whose size is larger than the specified value will fail with an EINVAL error.

This parameter specifies only the largest value the operating system can accept for the size of a shared memory segment. Whether the segment can be created depends entirely on the amount of swap space available on the system and, for a 32-bit process, whether there is enough space available in the process's address space for the segment to be attached.

Data Type

Unsigned long

Default

8,388,608

Range

0 - MAXUINT32 on 32-bit systems, 0 – MAXUINT64 on 64-bit systems

Units

Bytes

Dynamic?

No. Loaded into shmmax field of shminfo structure.

Validation

None

When to Change

When the default value is too low. Generally changed at the recommendation of software vendors, but unless the size of a shared memory segment needs to be constrained, setting this parameter to the maximum possible value has no side effects.

Commitment Level

Unstable