The software described in this documentation is either in Extended Support or Sustaining Support. See https://www.oracle.com/us/support/library/enterprise-linux-support-policies-069172.pdf for more information.
Oracle recommends that you upgrade the software described by this documentation as soon as possible.
The following parameters control aspects of system performance:
fs.file-max
Specifies the maximum number of open files for all processes. Increase the value of this parameter if you see messages about running out of file handles.
net.core.netdev_max_backlog
Specifies the size of the receiver backlog queue, which is used if an interface receives packets faster than the kernel can process them. If this queue is too small, packets are lost at the receiver, rather than on the network.
net.core.rmem_max
Specifies the maximum read socket buffer size. To minimize network packet loss, this buffer must be large enough to handle incoming network packets.
net.core.wmem_max
Specifies the maximum write socket buffer size. To minimize network packet loss, this buffer must be large enough to handle outgoing network packets.
net.ipv4.tcp_available_congestion_control
Displays the TCP congestion avoidance algorithms that are
available for use. Use the modprobe command
if you need to load additional modules such as
tcp_htcp
to implement the
htcp
algorithm.
net.ipv4.tcp_congestion_control
Specifies which TCP congestion avoidance algorithm is used.
net.ipv4.tcp_max_syn_backlog
Specifies the number of outstanding SYN
requests that are allowed. Increase the value of this parameter
if you see synflood
warnings in your logs,
and investigation shows that they are occurring because the
server is overloaded by legitimate connection attempts.
net.ipv4.tcp_rmem
Specifies minimum, default, and maximum receive buffer sizes
that are used for a TCP socket. The maximum value cannot be
larger than net.core.rmem_max
.
net.ipv4.tcp_wmem
Specifies minimum, default, and maximum send buffer sizes that
are used for a TCP socket. The maximum value cannot be larger
than net.core.wmem_max
.
vm.swappiness
Specifies how likely the kernel is to write loaded pages to swap rather than drop pages from the system page cache. When set to 0, swapping only occurs to avoid an out of memory condition. When set to 100, the kernel swaps aggressively. For a desktop system, setting a lower value can improve system responsiveness by decreasing latency. The default value is 60.
This parameter is intended for use with laptops to reduce power consumption by the hard disk. Do not adjust this value on server systems.