0 to 32,767

to:

0 to 50% of physical memory.

Limit on the number of shared memory segments that any one process can create.

to:

Limit on the number of shared memory segments that any one process can attach.

Maximum size of system V shared memory segment that can be created. This parameter is an upper limit that is checked before the system sees if it actually has the physical resources to create the requested memory segment.

to:

Maximum size of system V shared memory segment that can be created. This parameter is an upper limit that is checked before the system sees if it actually has the physical resources to create the requested memory segment.

Attempts to create a shared memory section whose size is zero or whose size is larger than the specified value will fail with an EINVAL error.

1,048,576

to:

8,388,608

to:

One page or 4% of physical memory, whichever is greater.

Bytes

to:

Pages

1 millisecond to 20 seconds

to:

1 millisecond to 2 hours

For applications, such as web servers that might receive excessive connection requests, you can increase the default value to match the incoming rate.

The following explains the relationship between tcp_conn_req_max_q0 and the maximum number of pending connections for each socket.

When a connection request is received, TCP first checks if the number (N) of pending TCP connections (three-way handshake is done) waiting to be accepted exceeds the maximum for the listener. If the connections are excessive, the request is denied. If the number of connections is allowable, then TCP checks if the number of incomplete pending TCP connections exceeds the sum of N and tcp_conn_req_max_q0. If it does not, the request is accepted. Otherwise, the oldest incomplete pending TCP request is dropped.

to:

For applications, such as web servers that might receive excessive connection requests, you can increase the default value to match the incoming rate.

The following explains the relationship between tcp_conn_req_max_q0 and the maximum number of pending connections for each socket.

When a connection request is received, TCP first checks if the number of pending TCP connections (three-way handshake is done) waiting to be accepted exceeds the maximum (N) for the listener. If the connections are excessive, the request is denied. If the number of connections is allowable, then TCP checks if the number of incomplete pending TCP connections exceeds the sum of N and tcp_conn_req_max_q0. If it does not, the request is accepted. Otherwise, the oldest incomplete pending TCP request is dropped.