Chapter 5
Network Cache and Accelerator (NCA) Tunable Parameters
This chapter describes some of the Network Cache and Accelerator
(NCA) tunable parameters.
Where to Find Tunable Parameter Information
Overview of 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 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, which
causes many TCP connections to be grouped together in the same hashtable entry.
This situation is indicated when NCA is receiving a lot of TCP connections
and system performance decreases.
|
| Commitment Level | Unstable
|
nca:nca_conn_req_max_q
| Description | 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 a lot of TCP connections
and can handle a larger load, but is refusing any more connections, increase
this parameter to allow NCA to handle more simultaneous TCP connections.
|
| Commitment Level | Unstable
|
nca:nca_conn_req_max_q0
| Description | 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 a lot of TCP connections and can handle
a larger load, but is refusing any more connections, increase this parameter
to allow NCA to handle more simultaneous TCP connections.
|
| Commitment Level | Unstable
|
nca:nca_ppmax
| Description | Maximum amount of physical
memory (in pages) used by NCA for caching the pages. Should not be
more than 75% of total memory.
|
| Default | 25% of physical memory
|
| Range | 1% to maximum amount of physical
memory
|
| Dynamic? | No
|
| When to Change | When using NCA on
a system with a lot of memory (greater than 512 Mbytes). If a system has a
lot of physical memory that is not being used, increase this parameter so
NCA will efficiently use this memory to cache new objects, and therefore,
increase system performance.
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 get your system's page size.
|
| Commitment Level | Unstable
|
nca:nca_vpmax
| Description | Maximum amount of virtual
memory (in pages) used by NCA for caching pages. Should not be more
than 75% of the total memory.
|
| Default | 25% of virtual memory
|
| Range | 1% to maximum amount of virtual
memory
|
| Dynamic? | No
|
| When to Change | When using NCA on
a system with a lot of memory (greater than 512 Mbytes). If a system has a
lot of virtual memory that is not being used, increase this parameter so NCA
will efficiently use this memory to cache new objects, and therefore, increase
system's performance.
This parameter should be increased in conjunction with nca_ppmax. Set this parameter approximately same as nca_vpmax
unless you have a system with more physical memory than virtual memory.
|
| Commitment Level | Unstable
|
