Tracing from the server console
To trace the driver from the server, you must first issue the proper commands.
Issue the TRACE ENABLE and TRACE BEGIN commands to trace the driver from the server.
The IBM
Storage Protect device driver
actually consists of two drivers: one for library-autochanger devices
and one for tape devices. You might choose which one you want to trace.
The following syntax is for the command:
DDTRACE START [ LIBRARYDD | TAPEDD]
[flags=EE |, FULL |, SYSLOG | BASE ]
DDTRACE GET [ LIBRARYDD | TAPEDD]
DDTRACE END [ LIBRARYDD | TAPEDD]
The following options are available:[flags=EE |, FULL |, SYSLOG | BASE ]
DDTRACE GET [ LIBRARYDD | TAPEDD]
DDTRACE END [ LIBRARYDD | TAPEDD]
- START
- Turns on tracing and writes the trace to a memory buffer based on the default or specified FLAGS option.
- GET
- Writes the memory buffer to the same file that was specified with the server TRACE BEGIN command.
- END
- Stops writing trace to the memory buffer but does not wipe out the contents of the buffer, so you might run END before running GET.
- LIBRARYDD
- Traces the device driver that controls library-autochangers.
- TAPEDD
- Traces the device driver that controls tape drives.
For the options listed above, you might specify
any one device driver or the library device driver, and one of the
other two. These are space delimited. For example:
- DDTRACE START TAPEDD - Starts tracing the device driver that controls tape drives.
- DDTRACE START LIBRARYDD Starts tracing the library-autochanger.
- DDTRACE START LIBRARYDD TAPEDD Traces both the library and the tape drives.
Whichever of these you use, specify the same ones for all commands in the start-get-end series.
The FLAGS parameter
is optional and usually not required. The following values are for
the FLAGS parameter:
- EE
- Traces all device driver routine entries and exits.
- FULL
- Turns on more debug tracing and provides more detail. Because the memory buffer size is fixed, however, fewer events are traced. Does not trace routine entry and exit points.
- SYSLOG
- On some platforms, SYSLOG directs the trace statements to be written to the system log in addition to the memory buffer. This offering is most useful in debugging kernel stoppages or in when the trace wraps in the memory buffer.
- BASE
- BASE is the default and cannot be specified with any other flags. It is only used to turn off the EE, FULL, and SYSLOG flags without turning off trace.