sysdumpdev Command

Commands Reference, Volume 5

sysdumpdev Command

Purpose

Changes the primary or secondary dump device designation in a running system.

Syntax

sysdumpdev [-c | -C] -P { -p Device | -s Device } [ -q ]

sysdumpdev [-c | -C] [ -p Device | -s Device] [ -q ]

sysdumpdev [-c | -C] [ -d Directory | -D Directory | -e | [ -k | -K ] | -l | -L | -p Device | -q | -r Host: Path | -s Device | -z ]

Description

The sysdumpdev command changes the primary or secondary dump device designation in a system that is running. The primary and secondary dump devices are designated in a system configuration object. The new device designations are in effect until the sysdumpdev command is run again, or the system is restarted.

If no flags are used with the sysdumpdev command, the dump devices defined in the SWservAt ODM object class are used. The default primary dump device is /dev/hd6. The default secondary dump device is /dev/sysdumpnull.

Notes:
A mirrored paging space may be used as a dump device.

Do not use a diskette drive as your dump device.

If you use a paging device, only use hd6, the primary paging device. AIX Version 4.2.1 or later supports using any paging device in the root volume group (rootvg) as the secondary dump device.

You can use the Web-based System Manager Devices application (wsm devices fast path) to run this command. You could also use the System Management Interface Tool (SMIT) smit sysdumpdev fast path to run this command.

You can also use the sysdumpdev command to specify whether or not dumps should be compressed before writing them to the dump device. Compressing dumps reduces the size needed for dump devices, but may cause the dump process to take longer.

Notes:
The savecore command should be used to copy a compressed dump from the dump device to a file.

The dump compression feature only applies to AIX Version 4.3.2 and later versions.

Running sysdumpdev in Non-rootvg Volume Groups

You can use a dump logical volume outside the root volume group, if it is not a permanent dump device. For example, if the -P flag is not specified. However, if you choose a paging space, we cannot copy the dump device unless it is in rootvg. During the time we must copy the dump device, only rootvg is active before paging is started.

The primary dump devices must always be in the root volume group for permanent dump devices. The secondary device may be outside the root volume group unless it is a paging space.

Configuring Remote Dump Devices with sysdumpdev

The sysdumpdev command can also be used to configure remote dump devices. The following conditions must be met before a remote dump device can be configured:

The local and the remote host must have Transmission Control Protocol/Internet Protocol (TCP/IP) installed and configured.
The local host must have Network File System (NFS) installed.
The remote host must support NFS.
The remote host must be operational and on the network. This condition can be tested by issuing the ping command.
The remote host must have an NFS exported directory defined such that the local host has read and write permissions as well as root access to the dump file on the remote host.
The remote host cannot be the same as the local host.

The network device driver must support remote dump. Drivers which support remote dump include the drivers for these network devices:

Integrated Ethernet MCA Adapter
IBM 10/100 Mbps Ethernet TX MCA Adapter (8f62)
IBM PCI Ethernet Adapter (22100020)
IBM 10/100 Mbps Ethernet PCI Adapter (23100020)
FDDI MCA Adapter
ISA Token Ring Adapter
Token-Ring High-Performance Adapter (8fa2)
Token-Ring High-Performance Adapter (8fc8)
IBM PCI Token-Ring Adapter (14101800)
IBM PCI Token-Ring Adapter (14103e00)

Drivers that do not support remote dump include the drivers for these network devices:

ISA Ethernet Adapter
Ethernet High-Performance LAN Adapter (8ef5)
Ethernet High-Performance LAN Adapter (8f95)
Gigabit Ethernet-SX PCI Adapter (14100401)

Flags

-c	Specifies that dumps will not be compressed. The -c flag applies to only AIX Version 4.3.2 and later versions.
-C	Specifies that all future dumps will be compressed before they are written to the dump device. The -C flag applies to only AIX Version 4.3.2 and later versions.
-d Directory	Specifies the Directory the dump is copied to at system boot. If the copy fails at boot time, the -d flag ignores the system dump.
-D Directory	Specifies the Directory the dump is copied to at system boot. If the copy fails at boot time, using the -D flag allows you to copy the dump to an external media. Note: When using the -d Directory or -D Directory flags, the following error conditions are detected: Directory does not exist. Directory is not in the local journaled file system. Directory is not in the rootvg volume group.

-e	Estimates the size of the dump (in bytes) for the current running system. If the dump will be compressed, then the size shown is the estimate of the size after compression.
-k	Requires the key mode switch to be in the service position before a dump can be forced with the reset button or the dump key sequences. This is the default setting.
-K	The reset button or the dump key sequences will force a dump with the key in the normal position, or on a machine without a key mode switch. Note: On a machine without a key mode switch, a dump can not be forced with the reset button nor the key switch without this value set.
-l	Lists the current value of the primary and secondary dump devices, copy directory, and forcecopy attribute.
-L	Displays statistical information about the most recent system dump. This includes date and time of last dump, number of bytes written, and completion status. If the dump was compressed, then this flag shows both the original uncompressed size and the compressed size of the dump. The compressed size is the size of what was actually written to the dump device.
-P	Makes permanent the dump device specified by -p or -s flags. The -P flag can only be used with the -p or -s flags.
-p Device	Temporarily changes the primary dump device to the specified device. The device can be a logical volume or a tape device. For a network dump, the device can be a host name and a path name.
-q	Suppresses all messages to standard output. If this flag is used with the -l, -r, -z or -L flag, the -q command will be ignored.
-r Host:Path	Frees space used by the remote dump file on server Host. The location of the dump file is specified by the Path.
-s Device	Temporarily changes the secondary dump device to the specified device. The device can be a logical volume or a tape device. For a network dump, the device can be a host name and a path name.
-z	Determines if a new system dump is present. If one is present, a string containing the size of the dump in bytes and the name of the dump device will be written to standard output. If a new system dump does not exist, nothing is returned. After the sysdumpdev -z command is run on an existing system dump, the dump will no longer be considered recent.

If no flags are used with the sysdumpdev command, the default dump devices are used.

Security

Access Control: Only the root user can run this command.

Examples

To display current dump device settings, enter:
```
sysdumpdev -l
```
To designate logical volume hd7 as the primary dump device, enter:
```
sysdumpdev -p /dev/hd7
```
To designate tape device rmt0 as the secondary dump device, enter:
```
sysdumpdev -s /dev/rmt0
```
To display information from the previous dump invocation, enter:
```
sysdumpdev -L
```
To permanently change the database object for the primary dump device to /dev/newdisk1, enter:
```
sysdumpdev -P -p /dev/newdisk1
```
To determine if a new system dump exists, enter:
```
sysdumpdev -z
```
If a system dump has occurred recently, output similar to the following will appear:
```
4537344 /dev/hd7
```
To designate remote dump file /var/adm/ras/systemdump on host mercury for a primary dump device, enter:
```
sysdumpdev -p mercury:/var/adm/ras/systemdump
```
A : (colon) must be inserted between the host name and the file name.
To specify the directory that a dump is copied to after a system crash, if the dump device is /dev/hd6, enter:
```
sysdumpdev -d /tmp/dump
```
This attempts to copy the dump from /dev/hd6 to /tmp/dump after a system crash. If there is an error during the copy, the system continues to boot and the dump is lost.
To specify the directory that a dump is copied to after a system crash, if the dump device is /dev/hd6, enter:
```
sysdumpdev -D /tmp/dump
```
This attempts to copy the dump from /dev/hd6 to the /tmp/dump directory after a crash. If the copy fails, you are prompted with a menu that allows you to copy the dump manually to some external media.

Related Information

The crash command, mount command, ping command, savecore command, sysdumpstart command.

System Dump Facility in AIX Problem Solving Guide and Reference.

Setting up and running Web-based System Manager in AIX Version 4.3 System Management Guide: Operating System and Devices.