Tuning NCA Parameters

Setting these parameters is appropriate on a system that is a dedicated web server. These parameters allocate more memory for caching pages. You can set all of the tuning parameters described in this chapter in the /etc/system file.

For information on adding tunable parameters to the /etc/system file, see Tuning the Solaris Kernel.

`nca:nca_conn_hash_size`

Description: Controls the hash table size in the NCA module for all TCP connections, adjusted to the nearest prime number.
Default: 383 hash table entries
Range: 0 to 201,326,557
Dynamic?: No
When to Change: When the NCA's TCP hash table is too small to keep track of the incoming TCP connections. This situation causes many TCP connections to be grouped together in the same hashtable entry. This situation is indicated when NCA is receiving many TCP connections, and system performance decreases.
Commitment Level: Unstable

`nca:nca_conn_req_max_q`

Description: Defines the maximum number of pending TCP connections for NCA to listen on.
Default: 256 connections
Range: 0 to 4,294,967,295
Dynamic?: No
When to Change: When NCA closes a connection immediately after it is established because it already has too many established TCP connections. If NCA is receiving many TCP connections and can handle a larger load, but is refusing any more connections, increase this parameter. Doing so allows NCA to handle more simultaneous TCP connections.
Commitment Level: Unstable

`nca:nca_conn_req_max_q0`

Description: Defines the maximum number of incomplete (three-way handshake not yet finished) pending TCP connections for NCA to listen on.
Default: 1024 connections
Range: 0 to 4,294,967,295
Dynamic?: No
When to Change: When NCA refuses to accept any more TCP connections because it already has too many pending TCP connections. If NCA is receiving many TCP connections and can handle a larger load, but is refusing any more connections, increase this parameter. Doing so allows NCA to handle more simultaneous TCP connections.
Commitment Level: Unstable

`nca:nca_ppmax`

Description

Specifies the maximum amount of physical memory (in pages) used by NCA for caching the pages. This value should not be more than 75 percent of total memory.

Default

25 percent of physical memory

Range

1 percent to maximum amount of physical memory

Dynamic?

When to Change

When using NCA on a system with more than 512 Mbytes of memory. If a system has a lot of physical memory that is not being used, increase this parameter. Then, NCA will efficiently use this memory to cache new objects. As a result, system performance will increase.

This parameter should be increased in conjunction with nca_vpmax, unless you have a system with more physical memory than virtual memory (a 32-bit kernel that has greater than 4 Gbytes memory). Use pagesize(1) to determine your system's page size.

Commitment Level

Unstable

`nca:nca_vpmax`

Description

Specifies the maximum amount of virtual memory (in pages) used by NCA for caching pages. This value should not be more than 75 percent of the total memory.

Default

25 percent of virtual memory

Range

1 percent to maximum amount of virtual memory

Dynamic?

When to Change

When using NCA on a system with more than 512 Mbytes of memory. If a system has a lot of virtual memory that is not being used, increase this parameter. Then, NCA will efficiently use this memory to cache new objects. As a result, system performance will increase.

This parameter should be increased in conjunction with nca_ppmax. Set this parameter about the same value as nca_vpmax, unless you have a system with more physical memory than virtual memory.

Commitment Level

Unstable