Sun Java System Access Manager 7.1 Performance Tuning and Troubleshooting Guide

Operating System (OS) Considerations

Solaris OS

Sun Fire T1000 and T2000 Servers

If Access Manager is installed on a Sun Fire T1000 or T2000 server, the tuning scripts for Web Server 7.0 and Application Server 8.2 set the JVM GC ParallelGCThreads parameter to 8:

-XX:ParallelGCThreads=8

This parameter reduces the number of garbage collection threads, which could be unnecessarily high on a 32-thread capable system. However, you can increase the value to 16 or even 20 for a 32 virtual CPU machine such as a Sun Fire T1000 server, if it minimizes full garbage collection activities.

Solaris SPARC Systems with CMT Processor with CoolThreads Technology

For Solaris SPARC systems with CMT processor with CoolThreads technology, in the /etc/opt/SUNWam/config/AMConfig.properties file, it is recommended that you add the following properties at the end of the file:

com.sun.identity.log.resolveHostName=false
com.sun.am.concurrencyRate=value

where value depends on the number of cores in a Sun Fire T1000 or T2000 server. For example, for 8 cores, set value to 8, or for 6 cores, set value to 6.

Linux OS

To tune for maximum performance on Linux systems, you need to make tuning adjustments to the following items:

Note –

If you are running Application Server 8.1 on Red Hat Linux, the stack size of the threads created by the Red Hat OS for Application Server is 10 Mbytes, which can cause JVM resource problems (CR 6223676). To prevent these problems, set the Red Hat OS operating stack size to a lesser value such as 2048 or even 256 Kbytes, by executing the ulimit command before you start Application Server. Execute the ulimit command on the same console that you will use to start Application Server. For example:

ulimit -s 256

File Descriptors

You might need to increase the number of file descriptors from the default. Having a higher number of file descriptors ensures that the server can open sockets under high load and not abort requests coming in from clients. Start by checking system limits for file descriptors with this command:

cat /proc/sys/fs/file-max
8192

The current limit shown is 8192. To increase it to 65535, use the following command (as root):

echo "65535" > /proc/sys/fs/file-max

To make this value to survive a system reboot, add it to /etc/sysctl.conf and specify the maximum number of open files permitted:

fs.file-max = 65535

Note: The parameter is not proc.sys.fs.file-max, as you might expect.

To list the available parameters that can be modified using sysctl:

sysctl -a

To load new values from the sysctl.conf file:

sysctl -p /etc/sysctl.conf

To check and modify limits per shell, use the following command:

limit

The output will look something like this:

cputime         unlimited
filesize        unlimit
datasize        unlimited
stacksize       8192 kbytes
coredumpsize    0 kbytes
memoryuse       unlimited
descriptors     1024
memorylocked    unlimited
maxproc         8146
openfiles       1024

The openfiles and descriptors show a limit of 1024. To increase the limit to 65535 for all users, edit /etc/security/limits.conf as root, and modify or add the nofile setting (number of file) entries:

*         soft    nofile                     65535
*         hard    nofile                     65535

The asterisk (*) is a wildcard that identifies all users. You could also specify a user ID instead.

Then edit /etc/pam.d/login and add the line:

session required /lib/security/pam_limits.so

On Red Hat Linux , you also need to edit /etc/pam.d/sshd and add the following line:

session required /lib/security/pam_limits.so

On many systems, this procedure will be sufficient. Log in as a regular user and try it before doing the remaining steps. The remaining steps might not be required, depending on how pluggable authentication modules (PAM) and secure shell (SSH) are configured.

Virtual Memory

To change virtual memory settings, add the following to /etc/rc.local:

echo 100 1200 128 512 15 5000 500 1884 2 > /proc/sys/vm/bdflush

For more information, view the man pages for bdflush.

Network Interface

To ensure that the network interface is operating in full duplex mode, add the following entry into /etc/rc.local:

mii-tool -F 100baseTx-FD eth0

where eth0 is the name of the network interface card (NIC).

Disk I/O Settings

To tune disk I/O performance for a non-SCSI disk, follow these steps:

Test the disk speed with this command:
```
 /sbin/hdparm -t /dev/hdX
```
Enable direct memory access (DMA) with this command:
```
/sbin/hdparm -d1 /dev/hdX
```
Check the speed again using the hdparm command. Given that DMA is not enabled by default, the transfer rate might have improved considerably. In order to do this at every reboot, add the /sbin/hdparm -d1 /dev/hdX line to /etc/conf.d/local.start, /etc/init.d/rc.local, or whatever the startup script is called.

TCP/IP Settings

To tune the TCP/IP settings, follow these steps:

Add the following entry to /etc/rc.local:

echo 30 > /proc/sys/net/ipv4/tcp_fin_timeout
echo 60000 > /proc/sys/net/ipv4/tcp_keepalive_time
echo 15000 > /proc/sys/net/ipv4/tcp_keepalive_intvl
echo 0 > /proc/sys/net/ipv4/tcp_window_scaling

Add the following to /etc/sysctl.conf:

# Disables packet forwarding
net.ipv4.ip_forward = 0
# Enables source route verification
net.ipv4.conf.default.rp_filter = 1
# Disables the magic-sysrq key
kernel.sysrq = 0
net.ipv4.ip_local_port_range = 1204 65000
net.core.rmem_max = 262140
net.core.rmem_default = 262140
net.ipv4.tcp_rmem = 4096 131072 262140
net.ipv4.tcp_wmem = 4096 131072 262140
net.ipv4.tcp_sack = 0
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_window_scaling = 0
net.ipv4.tcp_keepalive_time = 60000
net.ipv4.tcp_keepalive_intvl = 15000
net.ipv4.tcp_fin_timeout = 30

Add the following as the last entry in /etc/rc.local:
```
sysctl -p /etc/sysctl.conf
```
Reboot the system.
Use this command to increase the size of the transmit buffer:
```
tcp_recv_hiwat ndd /dev/tcp 8129 32768
```