Kernel Extensions and Device Support Programming Concepts

Copying a System Dump

Your dump device holds the information that a system dump generates, whether generated by the system or a user. You can copy this information to tape and deliver the material to your service department for analysis.

Note

If you intend to use a tape to send a snap image to IBM for software support. The tape must be one of the following formats: 8mm, 2.3 Gb capacity, 8mm, 5.0 Gb capacity, or 4mm, 4.0 Gb capacity. Using other formats will prevent or delay software support from being able to examine the contents.

There are two procedures for copying a system dump, depending on whether you're using a dataless workstation or a non-dataless machine:

Copying a System Dump on a Dataless Workstation

On a dataless workstation, the dump is copied to the server when the workstation is rebooted after the dump. The dump may not be available to the dataless machine.

Copy a system dump on a dataless workstation by performing the following tasks:

Reboot in Normal mode

To reboot in normal mode:

Switch off the power on your machine.
Turn the mode switch to the Normal position.
Switch on the power on your machine.

Locate the System Dump

To locate the dump:

Log on to the server .
Use the lsnim command to find the dump object for the workstation. (For this example, the workstation's object name on the server is worker .)
```
lsnim -l worker
```
The dump object appears on the line:
```
dump = dumpobject
```
Use the lsnim command again to determine the path of the object:
```
lsnim -l dumpobject
```
The path name displayed is the directory containing the dump. The dump usually has the same name as the object for the dataless workstation.

Copy the System Dump from the Server

The dump is copied like any other file. To copy the dump to tape, use the tar command:

tar -c

or, to copy to a tape other than /dev/rmt0:

tar -cftapedevice

To copy the dump back from the external media (such as a tape drive), use the tar command. Enter the following to copy the dump from /dev/rmt0:

tar -x

To copy the dump from any other media, enter:

tar -xftapedevice

Copying a System Dump on a Non-Dataless Machine

Copy a system dump on a non-dataless machine by performing the following tasks:

Reboot Your Machine
Copy the System Dump using one of the following methods:
- Copy a System Dump after Rebooting in Normal Mode
- Copy a System Dump after Booting from Maintenance Mode

Reboot Your Machine

Reboot in Normal mode using the following steps:

Switch off the power on your machine.
Turn the mode switch to the Normal position.
Switch on the power on your machine.

If your system brings up the login prompt, go to Copy a System Dump after Rebooting in Normal Mode.

If your system stops with a number in the operator panel display instead of bringing up the login prompt, reboot your machine from Maintenance mode, then go to Copy a System Dump after Booting from Maintenance Mode.

Copy a System Dump after Rebooting in Normal Mode

After rebooting in Normal mode, copy a system dump by doing the following:

Log in to your system as root user.
Copy the system dump to tape using the following snap command:
```
/usr/sbin/snap -gfkD -o /dev/rmt#
```
where # (pound sign) is the number of your available tape device (the most common is /dev/rmt0 ) . To find the correct number, enter the following lsdev command, and look for the tape device listed as Available:
```
lsdev -C -c tape -H
```
Note

If your dump went to a paging space logical volume, it has been copied to a directory in your root volume group, /var/adm/ras. See Configure a Dump Device and the sysdumpdev command for more details. These dumps are still copied by the snap command. The sysdumpdev -L command lists the exact location of the dump.
To copy the dump back from the external media (such as a tape drive), use the pax command. Enter the following to copy the dump from /dev/rmt0:
```
pax -rf/dev/rmt0
```
To copy the dump from any other media, enter:
```
tar -xftapedevice 
```

Copy a System Dump after Booting from Maintenance Mode

Note

Use this procedure only if you cannot boot your machine in Normal mode.

After booting from Maintenance mode, copy a system dump or tape using the following snap command:
```
/usr/sbin/snap -gfkD -o /dev/rmt#
```
To copy the dump back from the external media (such as a tape drive), use the tar command. Enter the following to copy the dump from /dev/rmt0:
```
tar -x 
```
To copy the dump from any other media, enter:
```
tar -xftapedevice 
```