Cisco Headend System Release 2.7 User Guide
Chapter 13 Monitor the Logfiles of DNCS Processes with the qtail and sesstail Utilities
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Design of the qtail and sesstail Utilities and the
System Logfiles
System Logfiles
Design of the qtail and sesstail Utilities
The UNIX operating system includes a utility called tail. The tail utility allows you
to monitor a file in real time; as a new line is written to a file, that line is instantly
displayed by the tail utility.
to monitor a file in real time; as a new line is written to a file, that line is instantly
displayed by the tail utility.
Note: To learn more about the tail utility, from an xterm window on the DNCS, type
man tail and press Enter.
man tail and press Enter.
In theory, you can use the tail utility to monitor the logfile of a DNCS process in real
time. The problem, however, comes when that logfile reaches its 50,000 line limit.
The tail utility has no way of knowing that a limit has been reached and that a new
logfile has been created. Hence, no new data can be observed in the logfile
monitored by the tail utility.
time. The problem, however, comes when that logfile reaches its 50,000 line limit.
The tail utility has no way of knowing that a limit has been reached and that a new
logfile has been created. Hence, no new data can be observed in the logfile
monitored by the tail utility.
The qtail utility uses the UNIX tail utility to monitor logfiles of DNCS processes in
real time. When the limit of a specific logfile is reached, however, the qtail utility
automatically starts monitoring the newly created file.
real time. When the limit of a specific logfile is reached, however, the qtail utility
automatically starts monitoring the newly created file.
The sesstail utility is very similar to the qtail utility but is specifically designed to
monitor the dsm process logfiles video-on-demand (VOD) session-related activities.
monitor the dsm process logfiles video-on-demand (VOD) session-related activities.
Design of the System Logfiles
A limit is placed on how large the logfiles in the /dvs/dncs/tmp directory can
grow. If the logfiles were designed to grow without limit, the logfiles might
eventually grow so large that they would slow down the performance of the DNCS.
By default, we place a 50,000 line limit on individual logfiles. Each DNCS process
supports up to 10 logfiles; the first logfile has a .000 extension, the second logfile has
a .001 extension, and so on.
grow. If the logfiles were designed to grow without limit, the logfiles might
eventually grow so large that they would slow down the performance of the DNCS.
By default, we place a 50,000 line limit on individual logfiles. Each DNCS process
supports up to 10 logfiles; the first logfile has a .000 extension, the second logfile has
a .001 extension, and so on.
Example:
camPsm.000
camPsm.001
camPsm.002
When a process reaches its 10-logfile limit, the system overwrites the first logfile
with new data. By supporting 10 logfiles, the DNCS allows system operators and
with new data. By supporting 10 logfiles, the DNCS allows system operators and