THE VIRTUAL SERVER HANDBOOK

Troubleshooting the Virtual

Server

The Virtual Server administrator is called upon to troubleshoot the errors

and problems that will come up from time to time. Many of the

troubleshooting steps have already been mentioned in this chapter.

Checking the quota

Remember when the quota hard limit is met, nothing can write to disk. E 

mail is not accepted, logs are not written, installs do not complete,

guestbooks and forms do not save to file. Remember the quota has the soft

limit and hard limit so you have time to fix the problem. If you go over

quota you can use the 

vnl 

and 

vdiskuse

 commands to fix the problem.

Checking the log files

Errors and system messages are logged in the Virtual Server log files. If you

are having problems with E mail or FTP check the ~/usr/log/messages file.

When users report problems with E mail or FTP the second thing support

checks after checking quotas is the messages file. Many times the error the

end user is reporting is an obscure client error. Checking the

~/usr/log/messages file will give more details on the error. It is extremely

useful to use the "tail" command to watch the messages as they are being

added to the log. This way you can see what is being added to the log as the

user duplicates the error. To do this do the following:

1. Telnet to your Virtual Server

2. At a command prompt type the following:

% tail  f ~/usr/log/messages

3. Have the user duplicate the error while running the tail command.

The errors users get while browsing your web site are recorded in the

~/www/logs/error_log file. Once again the error on the browser may not

have a lot of useful information while the error log has specific messages.

You can use the above tail command to watch the log while you duplicate

the error.

Checking the processes

If you are getting errors, check the current processes running.  Use the top

and ps commands to check the processes currently running. It is not

uncommon to have a CGI not closing properly and that uses all of the

Virtual Servers capacity. Occasionally the popper process may hang when a

user s connection is terminated improperly. When checking top look at the

time a process has been running.  If it is idle and has been running for a

long time it may be hung and causing you some problems.

COPYRIGHT 

 1999  DIGITAL TOOLS  LLC.

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