Tuning for the Solaris OS

Tuning Parameters
File Descriptor Setting

Tuning Parameters

Tuning Solaris TCP/IP settings benefits programs that open and close many sockets. Since the GlassFish Server operates with a small fixed set of connections, the performance gain might not be significant.

The following table shows Solaris tuning parameters that affect performance and scalability benchmarking. These values are examples of how to tune your system for best performance.

Table 5-1 Tuning Parameters for Solaris

Parameter	Scope	Default	Tuned Value	Comments
`rlim_fd_max`	`/etc/system`	65536	65536	Limit of process open file descriptors. Set to account for expected load (for associated sockets, files, and pipes if any).
`rlim_fd_cur`	`/etc/system`	1024	8192
`sq_max_size`	`/etc/system`	2	0	Controls streams driver queue size; setting to 0 makes it infinite so the performance runs won’t be hit by lack of buffer space. Set on clients too. Note that setting `sq_max_size` to 0 might not be optimal for production systems with high network traffic.
`tcp_close_wait_interval`	`ndd /dev/tcp`	240000	60000	Set on clients too.
`tcp_time_wait_interval`	`ndd /dev/tcp`	240000	60000	Set on clients too.
`tcp_conn_req_max_q`	`ndd /dev/tcp`	128	1024
`tcp_conn_req_max_q0`	`ndd /dev/tcp`	1024	4096
`tcp_ip_abort_interval`	`ndd /dev/tcp`	480000	60000
`tcp_keepalive_interval`	`ndd /dev/tcp`	7200000	900000	For high traffic web sites, lower this value.
`tcp_rexmit_interval_initial`	`ndd /dev/tcp`	3000	3000	If retransmission is greater than 30-40%, you should increase this value.
`tcp_rexmit_interval_max`	`ndd /dev/tcp`	240000	10000
`tcp_rexmit_interval_min`	`ndd /dev/tcp`	200	3000
`tcp_smallest_anon_port`	`ndd /dev/tcp`	32768	1024	Set on clients too.
`tcp_slow_start_initial`	`ndd /dev/tcp`	1	2	Slightly faster transmission of small amounts of data.
`tcp_xmit_hiwat`	`ndd /dev/tcp`	8129	32768	Size of transmit buffer.
`tcp_recv_hiwat`	`ndd /dev/tcp`	8129	32768	Size of receive buffer.
`tcp_conn_hash_size`	`ndd /dev/tcp`	512	8192	Size of connection hash table. See Sizing the Connection Hash Table.

Sizing the Connection Hash Table

The connection hash table keeps all the information for active TCP connections. Use the following command to get the size of the connection hash table:

ndd -get /dev/tcp tcp_conn_hash

This value does not limit the number of connections, but it can cause connection hashing to take longer. The default size is 512.

To make lookups more efficient, set the value to half of the number of concurrent TCP connections that are expected on the server. You can set this value only in /etc/system, and it becomes effective at boot time.

Use the following command to get the current number of TCP connections.

netstat -nP tcp|wc -l

File Descriptor Setting

On the Solaris OS, setting the maximum number of open files property using ulimit has the biggest impact on efforts to support the maximum number of RMI/IIOP clients.

To increase the hard limit, add the following command to /etc/system and reboot it once:

set rlim_fd_max = 8192

Verify this hard limit by using the following command:

ulimit -a -H

Once the above hard limit is set, increase the value of this property explicitly (up to this limit) using the following command:

ulimit -n 8192

Verify this limit by using the following command:

ulimit -a

For example, with the default ulimit of 64, a simple test driver can support only 25 concurrent clients, but with ulimit set to 8192, the same test driver can support 120 concurrent clients. The test driver spawned multiple threads, each of which performed a JNDI lookup and repeatedly called the same business method with a think (delay) time of 500 ms between business method calls, exchanging data of about 100 KB. These settings apply to RMI/IIOP clients on the Solaris OS.

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	Oracle GlassFish Server 3.1 Performance Tuning Guide