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

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