Default Port Range

To enable Fast Communications Manager (FCM), a port or port range must be reserved in the services file on each server in the partitioned database system. At a minimum, the services file must contain one entry for each database partition within a particular server. The services file is located as follows :

• On Linux and UNIX : /etc/services

• On Windows : c:\winnt\system32\drivers\etc\services

You can define DB2 port entries using one of the following formats; however, format #2 is recommended:

Format #1 : Define a group of port names with a port range:

  port_name                           port_number   ---------                           -----------   DB2_v8inst                          60000/tcp   DB2_v8inst_END                      60003/tcp  

Format #2 : Define a specific port name and port range to a database partition:

  port_name                           port_number   ---------                           -----------   DB2_v8inst                          60000/tcp   DB2_v8inst_1                        60001/tcp   DB2_v8inst_2                        60002/tcp   DB2_v8inst_END                      60003/tcp  

where:

port_name is the name of the partitioned instance. For the first port entry, the port name must be the name of the instance (v8inst), preceded by DB2_. In this example, the first port name is DB2_v8inst. For the second port entry or subsequence port entry, the port name must be the name of the instance, preceded by DB2_ and suffixed by _n, where n is incremented by 1. In this example, the second port name is DB2_v8inst_1, and the third port name is DB2_v8inst_2. For the last port entry, the port name must be the name of the instance, preceded by DB2_ and suffixed by _END. In this example, the last port entry is DB2_v8inst_END.

port_number is the port number that you reserve for database partition server communications. For best practices, reserve one port number for each database partition per server (host name).

• Same port must be reserved on all servers

• Must be followed by /tcp

NOTE

To avoid conflict with other applications, it is recommended to use high values for DB2 port numbers and reserve a few extra ports for future growth.

Sample db2nodes.cfg and /etc/services Configuration

Let's look at some following db2nodes.cfg files, using the rules described above.

Scenario 1

Two servers, one database partition per server, two ports have been reserved:

  cat db2nodes.cfg   0                        server1                  0   1                        server2                  0   cat /etc/services  grep db2inst1   DB2_db2inst1             60000/tcp   DB2_db2inst1_END         60001/tcp  

Scenario 2

Two servers, two database partitions per server, four ports have been reserved. Because there are multiple database partitions on the same server, the first port number must start at 0 and continue by 1 for each server:

  cat db2nodes.cfg   0                        server1                  0   1                        server1                  1   2                        server2                  0   3                        server2                  1   cat /etc/services  grep db2inst1   DB2_db2inst1             60000/tcp   DB2_db2inst1_1           60001/tcp   DB2_db2inst1_2           60002/tcp   DB2_db2inst1_END         60003/tcp  

Scenario 3

Three servers, two database partitions on server1, two database partitions on server2, and one database partition on server3, five ports have been reserved:

  cat db2nodes.cfg   0                        server1                  0   1                        server1                  1   2                        server2                  0   3                        server2                  1   4                        server3                  0   cat /etc/services  grep db2inst1   DB2_db2inst1             60000/tcp   DB2_db2inst1_1           60001/tcp   DB2_db2inst1_2           60002/tcp   DB2_db2inst1_3           60003/tcp   DB2_db2inst1_END         60004/tcp  

Scenario 4

Single Windows server name IBM-N2VQMD9FCEA, four database partitions, four ports have been reserved.

  cat c:\sqllib\db2\db2nodes.cfg   0                  IBM-N2VQMD9FCEA    IBM-N2VQMD9FCEA    0   1                  IBM-N2VQMD9FCEA    IBM-N2VQMD9FCEA    1   2                  IBM-N2VQMD9FCEA    IBM-N2VQMD9FCEA    2   3                  IBM-N2VQMD9FCEA    IBM-N2VQMD9FCEA    3   more c:\winnt\system32\drivers\etc\services\db2nodes.cfg  grep i db2   DB2_DB2            60000/tcp   DB2_DB2_1          60001/tcp   DB2_DB2_2          60002/tcp   DB2_DB2_END        60003/tcp  

Scenario 5

Two Windows servers, four database partitions on server IBM-N2VQMD9FCEA and two database partitions on server IBM-Y2KQMD9FCEB, six ports have been reserved.

  cat c:\sqllib\db2\db2nodes.cfg   0                      IBM-N2VQMD9FCEA       IBM-N2VQMD9FCEA        0   1                      IBM-N2VQMD9FCEA       IBM-N2VQMD9FCEA        1   2                      IBM-N2VQMD9FCEA       IBM-N2VQMD9FCEA        2   3                      IBM-N2VQMD9FCEA       IBM-N2VQMD9FCEA        3   4                      IBM-Y2KQMD9FCEB       IBM-Y2KQMD9FCEB        0   5                      IBM-Y2KQMD9FCEB       IBM-Y2KQMD9FCEB        1   more c:\winnt\system32\drivers\etc\services\db2nodes.cfg  grep i db2   DB2_DB2                60000/tcp   DB2_DB2_1              60001/tcp   DB2_DB2_2              60002/tcp   DB2_DB2_3              60003/tcp   DB2_DB2_4              60004/tcp   DB2_DB2_END            60005/tcp