How to solve db2start error SQL6048N

Technote (troubleshooting)

Problem(Abstract)

SQL6048N A communication error occurred during START or STOP DATABASE MANAGER processing.

Symptom

When trying to start an instance using the db2start command, the following error is received.

SQL6048N A communication error occurred during START or STOP DATABASE MANAGER processing.

Cause

The examples are shown below :

1. Your system might have a different hostname than the hostname listed in <INSTANCE_HOME>/sqllib/db2nodes.cfg

2.Your system might have a problem with rsh daemon.

Environment

DB2® V9.1, V9.5 and V9.7 on Linux™ or UNIX™ environments

Diagnosing the problem

1. Execute the hostname command and compare the output with the hostname listed in <INSTANCE_HOME>/sqllib/db2nodes.cfg

2. Login as a instance user and run the following command.
$ db2_all "echo OK" rshd: 0826-813 Permission is denied. rshd: 0826-813 Permission is denied.
Run the the following command to display related information:

db2 ? SQL6048N

Resolving the problem

Resolve the problem using one of these solutions:

If the hostname displayed by the hostname command is different than the hostname from <INSTANCE_HOME>/sqllib/db2nodes.cfg, then you must modify the db2nodes.cfg record to match the hostname of the system.
If the hostname of the system is a Fully Qualified Domain Name (FQDN) then you must use the FQDN in db2nodes.cfg.

3. Step 1 : Login as instance owner and change the permission of the .rhosts file as follows.

chmod 400 .rhosts

Step 2 : Run the following command to confirm if the rsh daemon is set properly or not.

$ db2_all "echo OK"

OK
coralpib135: echo OK completed ok

OK
coralpib137: echo OK completed ok

Step 3: Run the db2stop or db2start command.

$ db2stop
11/29/2011 01:45:13 0 0 SQL1064N DB2STOP processing was successful.
11/29/2011 01:45:13 1 0 SQL1064N DB2STOP processing was successful.
SQL1064N DB2STOP processing was successful.

This is one of the method to solve the MPP start problem. If user runs the db2 ? command, SQL6048N will display related information.

DB2 SQL6048N 在 START 或 STOP DATABASE MANAGER 处理期间发生通讯错误