NIS+ Performance and System Hang Problems

This section describes common slow performance and system hang problems.

Performance Problem Symptoms

Error messages with operative clauses such as:

• Busy try again later

• Not responding

Other common symptoms:

• You issue a command and nothing seems to happen for far too long.

• Your system, or shell, no longer responds to keyboard or mouse commands.

• NIS+ operations seem to run slower than they should or slower than they did before.

Checkpointing

Someone has issued an nisping or nisping -C command. Or the rpc.nisd daemon is performing a checkpoint operation.

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Caution -

Do not reboot! Do not issue any more nisping commands.

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When performing a nisping or checkpoint, the server will be sluggish or may not immediately respond to other commands. Depending on the size of your namespace, these commands may take a noticeable amount of time to complete. Delays caused by checkpoint or ping commands are multiplied if you, or someone else, enter several such commands at one time. Do not reboot. This kind of problem will solve itself. Just wait until the server finishes performing the nisping or checkpoint command.

During a full master-replica resync, the involved replica server will be taken out of service until the resync is complete. Do not reboot--just wait.

Variable NIS_PATH

Make sure that your NIS_PATH variable is set to something clean and simple. For example, the default: org_dir.$:$. A complex NIS_PATH, particularly one that itself contains a variable, will slow your system and may cause some operations to fail. (See "NIS_PATH Environment Variable" for more information.)

Do not use nistbladm to set nondefault table paths. Nondefault table paths will slow performance.

Table Paths

Do not use table paths because they will slow performance.

Too Many Replicas

Too many replicas for a domain degrade system performance during replication. There should be no more than 10 replicas in a given domain or subdomain. If you have more than five replicas in a domain, try removing some of them to see if that improves performance.

Recursive Groups

A recursive group is a group that contains the name of some other group. While including other groups in a group reduces your work as system administrator, doing so slows down the system. You should not use recursive groups.

Large NIS+ Database Logs at Start-up

When rpc.nisd starts up it goes through each log. If the logs are long, this process could take a long time. If your logs are long, you may want to checkpoint them using nisping -C before starting rpc.nisd.

The Master rpc.nisd Daemon Died

Symptoms:

If you used the -M option to specify that your request be sent to the master server, and the rpc.nisd daemon has died on that machine, you will get a "server not responding" type error message and no updates will be permitted. (If you did not use the -M option, your request will be automatically routed to a functioning replica server.)

Possible Cause:

Using uppercase letters in the name of a home directory or host can sometimes cause rpc.nisd to die.

Diagnosis:

First make sure that the server itself is up and running. If it is, run ps -ef | grep rpc.nisd to see if the daemon is still running.

Solution:

If the daemon has died, restart it. If rpc.nisd frequently dies, contact your service provider.

No nis_cachemgr

Symptoms:

It takes too long for a machine to locate namespace objects in other domains.

Possible Cause:

You do not have nis_cachemgr running.

Diagnosis:

Run ps -ef | grep nis_cachemgr to see if it is still running.

Solution

Start nis_cachemgr on that machine.

Server Very Slow at Start-up After NIS+ Installation

Symptoms:

A server performs slowly and sluggishly after using the NIS+ scripts to install NIS+ on it.

Possible Cause:

You forgot to run nisping -C -a after running the nispopulate script.

Solution:

Run nisping -C -a to checkpoint the system as soon as you are able to do so.

niscat Returns: Server busy. Try Again

Symptoms:

You run niscat and get an error message indicating that the server is busy.

Possible Cause:

• The server is busy with a heavy load, such as when doing a resync.

• The server is out of swap space.

Diagnosis:

Run swap -s to check your server's swap space.

Solution:

You must have adequate swap and disk space to run NIS+. If necessary, increase your space.

NIS+ Queries Hang After Changing Host Name

Symptoms:

Setting the host name for an NIS+ server to be fully qualified is not recommended. If you do so, and NIS+ queries then just hang with no error messages, check the following possibilities:

Possible Cause:

Fully qualified host names must meet the following criteria:

• The domain part of the host name must be the same as the name returned by the domainname command.

• After the setting the host name to be fully qualified, you must also update all the necessary /etc and /etc/inet files with the new host name information.

• The host name must end in a period.

Solution:

Kill the NIS+ processes that are hanging and then kill rpc.nisd on that host or server. Rename the host to match the two requirements listed above. Then reinitialize the server with nisinit. (If queries still hang after you are sure that the host is correctly named, check other problem possibilities in this section.)