Buffer Size

The DATABUFFERPOOLSIZE statement describes the buffers used to hold data during TCPIP virtual machine processing. You can modify the number of buffers and the size of each one. The number of data buffers is limited only by the amount of virtual storage. You should be careful to specify a sufficient number of data buffers. Running out of data buffers causes degraded performance and the abnormal termination of Telnet server connections.

The default buffer size is 8192 bytes (8 KB). Other specific sizes are permitted up to 262144 bytes (256 KB). For a list of the supported values, see the DATABUFFERPOOLSIZE statement in z/VM: TCP/IP Planning and Customization. Increasing the size of the buffers results in increased throughput for file transfers, but it may waste storage for other applications such as Telnet that send and receive smaller blocks of data.