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Commands Reference, Volume 5

sysdumpdev Command

Purpose

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

Syntax

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

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

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

sysdumpdev [ -c |  -C ] [ -i ]

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:
  1. A mirrored paging space may be used as a dump device.
  2. Do not use a diskette drive as your dump device.
  3. If you use a paging device, only use hd6, the primary paging device. AIX 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 Devices application in Web-based System Manager (wsm) 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:
  1. The savecore command should be used to copy a compressed dump from the dump device to a file.
  2. The dump compression feature only applies to AIX 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 network device driver must support remote dump. Drivers which support remote dump include the drivers for these network devices:

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

Flags

-c Specifies that dumps will not be compressed. The -c flag applies to only AIX 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 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.
-i Indicates that the sysdumpdev command was called from a system function. This flag is only used by system utilities. The -i flag will not make the requested change if the effected value has already been modified by other than an automatic IBM function; that is, the -i flag will not override a previous change.
-I Resets the indications of previous changes. After the -I flag is specified, changes are allowed with the -i flag.
-k If your machine has a key mode switch, it is required 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 If your machine has a key mode switch, 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.
Note
The dump sizes shown might not reflect the exact size of the dump on the media. There can be a small difference due to disk and copy block sizes.
-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

  1. To display current dump device settings, enter:
    sysdumpdev -l
  2. To designate logical volume hd7 as the primary dump device, enter:
    sysdumpdev -p /dev/hd7
  3. To designate tape device rmt0 as the secondary dump device, enter:
    sysdumpdev -s /dev/rmt0
  4. To display information from the previous dump invocation, enter:
    sysdumpdev -L
  5. To permanently change the database object for the primary dump device to /dev/newdisk1, enter:
    sysdumpdev -P -p /dev/newdisk1
  6. 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
  7. 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.
  8. 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.
  9. 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 mount command, ping command, savecore command, sysdumpstart command.

System Dump Facility in the AIX 5L Version 5.2 Kernel Extensions and Device Support Programming Concepts.

For information on installing the Web-based System Manager, see Chapter 2: Installation and System Requirements in AIX 5L Version 5.2 Web-based System Manager Administration Guide.

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