Installation guide

# echo 65536 > /proc/sys/fs/file-max

Alternatively, you can use sysctl(8) to change it:

# sysctl -w fs.file-max=65536

To make the change permanent, add or change the following line in the file /etc/sysctl.conf. This file is

used during the boot process. Oracle uses the following value in its validated configurations:

# echo "fs.file-max=327679" >> /etc/sysctl.conf

Adjusting Network Settings

Changing Network Kernel Settings

Oracle RAC now uses UDP as the default protocol on Linux for interprocess communication, such as cache fu-

sion buffer transfers between the instances. Starting with Oracle 10g, the network settings should be adjusted

for standalone databases as well.

Linux kernel 2.6 auto-tunes the default and maximum values of send and receive socket buffers. Oracle recom-

mends increasing them to satisfy installer checks. The kernel auto-tuning takes precedence of the specified de-

fault values but the specified static maximum takes precedence of the auto-tuned maximum.

Oracle recommends the default and maximum send buffer size (SO_SNDBUF socket option) and the default re-

ceive buffer size (SO_RCVBUF socket option) to be set to 256 KB. The recommended maximum receiver buffer

size is 2MB for Oracle 10.2 and 4MB for Oracle 11.1. The receive buffers are used by TCP and UDP to hold

the received data for the application until its read. This buffer cannot overflow because the sending party is not

allowed to send data beyond the buffer size window. This means that datagrams will be discarded if they do not

fit in the receive buffer. This could cause the sender to overwhelm the receiver.

The default and maximum window size can be changed in the proc file system without reboot:

Default setting in bytes of the socket receive buffer

# sysctl -w net.core.rmem_default=262144

Default setting in bytes of the socket send buffer

# sysctl -w net.core.wmem_default=262144

Maximum socket receive buffer size which may be set by using the SO_RCVBUF socket option

# sysctl -w net.core.rmem_max=4194304

Maximum socket send buffer size which may be set by using the SO_SNDBUF socket option

# sysctl -w net.core.wmem_max=262144