sysdumpdev Command

Purpose

Displays and modifies the information and settings that are related to the traditional system dump and a firmware-assisted system dump.

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 | [ -n | -N ] | -p device | -q | -s device | -z ]

sysdumpdev [ -i ]

sysdumpdev -L { -v | -S device }

sysdumpdev [ -t { traditional | fw-assisted  } ] [ -f { disallow, allow, require } ]

Description

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

If you run the sysdumpdev command with the no option, the sysdumpdev command identifies the current attributes of the primary and secondary dump devices and writes the attribute values to the object data manager (ODM) object class and nonvolatile random access memory (NVRAM). The default primary dump device is /dev/hd6 paging space. The default secondary dump device is /dev/sysdumpnull. If the system has a memory of 4 GB or more, the default dump device is /dev/lg_dumplv and the /dev/lg_dumplv is a dedicated dump device. AIX® 7.1, and later, extends the firmware-assisted dump capabilities to make it as the default system dump method if it is supported by the platform.

Note:

You can use the mirrored paging space as a dump device.
Do not use the diskette drive as your dump device.
If you use a paging device, use only the primary paging device, hd6. The AIX operating system supports the usage of any paging device in the root volume group (rootvg) as the secondary dump device.
If you use a removable device such as tape or DVD, the dump does not span the volumes. The dump must fit on a single volume.
You can configure an iSCSI software initiator device in the rootvg as the dump device for a firmware-assisted system dump, for AIX Version 6.1 with the 6100-01 Technology Level.
Remote dumps for thin servers are supported for AIX 6.1. Define the relative dump resource on the Network Installation Management (NIM) master to view the dump resource on the NIM client as an Internet Small Computer Systems Interface (iSCSI) disk that can only configure the primary dump device. Only a firmware-assisted system dump can be configured on an iSCSI disk device.
Only firmware-assisted system dump can be configured on a Non-Volatile Memory Express over Fabrics (NVMe-OF) disk device.
For AIX Version 6.1 with the 6100-06 Technology Level, you can configure a firmware-assisted dump of the kernel memory.
When you configure a dump device for a logical volume that is encrypted and locked, you might see an error message.
You cannot configure a dump device for a logical volume if the encryption or decryption of the logical volume is in progress.

For AIX 6.1 and later versions, all dumps are compressed. Use the savecore command to copy the dumps from the dump device to a file.

The sysdumpdev command supports the firmware-assisted system dump for the following features:

Return of the dump size estimation.
Display of information about the latest dump.
Detection of a new dump.

The sysdumpdev command provides the type of dump that includes the traditional dump type or the fw-assisted dump type.

The -t option specifies the type of dump. The possible values are traditional and fw-assisted.

The -f option specifies the full memory system dump mode. This mode is relevant only for the firmware-assisted system dump. In this mode, the dump is performed independent of the operating system. The partition memory is saved to the dump.

Running the sysdumpdev command in a Nonrootvg Volume Groups

You can use a dump-logical volume outside the root volume group, if it is not a permanent dump device and for a traditional system dump only. For example, if the -P option is not specified. However, if you choose a paging space, the dump device cannot be copied unless it is in the rootvg. If the dump device must be copied, only rootvg is active before you start the paging.

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

options

Item	Description
-d `directory`	Specifies the `directory` the dump is copied to at system boot. If the copy fails at boot time, you can use the -d option to ignore the system dump.
-D`directory`	Specifies the `directory` the dump is copied to at system boot. If the copy fails at boot time, you can use the -D option to copy the dump to an external media. Note: When you use the -d directory or -D`directory` options, 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. The size that is shown is the estimated size of the compressed dump.

Item	Description
-f{ `disallow` \| `allow_kernel` \| `require_kernel` \| `allow_full` \| `require_full` }	Specifies whether the firmware-assisted system dump allow, require, or forbid the dump of either the kernel memory or the full memory. In kernel memory or full memory mode, the dump is performed independently of the operating system. The kernel relevant memory is saved to a kernel memory system dump. The partition memory is saved to a full memory system dump. The -f option has the following variables: `disallow` Specifies that the full memory system dump mode and the kernel memory system dump mode are not allowed. It is the selective memory mode. `allow_full` Specifies that the full memory system dump mode is allowed but performs only when the operating system cannot handle the dump request. `require_full` Specifies that the full memory system dump mode is allowed and is always performed. When the full memory dump is allowed, the dump size estimation that is specified with the -e option corresponds to the memory size with the applied compression factor.
-i	Indicates that the sysdumpdev command was called from a system function. This option is only used by the system utilities. The -i option does not make the requested change if the affected value is modified by other than an automatic IBM function. The -i option does not override a previous change.
-I	Resets the indications of previous changes. After you specify the -I option, changes are allowed with the -i option.
-k	If your system has a key mode switch, it is required to be in the service position before a dump can be forced with the dump key sequences.
-K	If your system has a key mode switch, the reset button or the dump key sequences forces a dump with the key in the normal position, or on a machine without a key mode switch. Note: On a system without a key mode switch, a dump cannot be forced with the key sequence without this value set.
-l	Lists the current value of the primary and secondary dump devices, copy directory, and forcecopy attribute. The -l option displays the current dump type. The following list indicates the possible values that are displayed: `fw-assisted` The preferred dump type is firmware-assisted system dump. `fw-assisted (suspend)` The preferred dump type is firmware-assisted system dump, but the primary dump device is either not configured or it does not support firmware-assisted system dump. In the latter case, a traditional system dump is triggered. `traditional` Only the traditional system dump is available after the sysdumpdev -t traditional command as the firmware-assisted system dump is not supported on this system. To support the firmware-assisted system dump, sufficient memory must be available when the system starts, and POWER6 or later hardware and the supported firmware must be installed.
-n	Disables the Nest Accelerator GZIP (NX GZIP) dump compression. The system dump is compressed without using the NX GZIP.
-N	Enables the NX GZIP accelerated dump compression. The NX GZIP dump compression is only applicable to the firmware-assisted type system dumps.
-L	Displays the statistical information about the most recent system dump. Includes the date and time of the last dump, number of bytes written, and the completion status. The -L option shows both the compressed size and the uncompressed size of the dump. The compressed size is the size of what was written to the dump device. If no previous dump was recorded in nonvolatile memory, this option scans the dump devices for the existing dump. Note: The dump sizes that are shown might not reflect the exact size of the dump on the media. There can be a small difference because of disk and copy block sizes. If the dump fails due to an I/O error, the major and minor device numbers are those for the failing device.
-P	Makes permanent the dump device that the -p or -s options specify. The -P option can be used only with the -p or -s options.
-p `device`	Temporarily changes the primary dump device to the specified device. The device can be a logical volume, writable DVD, or a tape device or an iSCSI disk configured by the NIM for remote dump.
-q	Suppresses all messages to a standard output. If this option is used with the -l, -z, or -L option, the -q option is ignored.
-s `device`	Device Temporarily changes the secondary dump device to the specified device. The same devices valid for the -p option are valid here.
-S `device`	Scans a specific dump device for a valid compressed dump. The dump must be from an AIX release with a parallel dump support. You can use this option only with the -L option.
-t{`traditional` \| `fw-assisted`}	Specifies the type of dump to perform. The -t option has the following variables: `traditional` Specifies that the traditional system dump is performed. In this dump type, the dump data is saved before the system restart. You can specify only the `traditional` variable in any of the following circumstances: Firmware-assisted system dump is not supported. Memory is not sufficient when the system starts. POWER6 or later hardware is not installed. You cannot use the traditional system dump on an iSCSI software initiator dump device. `fw-assisted` Specifies that the firmware-assisted system dump is performed. In this dump type, the dump data is saved in a parallel dumb support with the system restart. If the system starts in a low memory configuration, you must explicitly enable the full memory dump by using the -f option. Specifically in an iSCSI software initiator configuration where a firmware-assisted system dump does not fall back on the traditional system dump if the full memory dump is not allowed. If you specify the `fw-assisted` variable but the primary dump device is not configured or it does not support firmware-assisted system dump, a traditional system dump is triggered. When the firmware-assisted system dump type is not allowed at a configuration time, or is not enforced at a dump request time, a traditional system dump is performed. In addition, as the scratch area is only reserved at initialization, a configuration change from traditional system dump to firmware-assisted system dump is not effective until you restart the system.
-v	When the dump status is not 0, this option displays the available dump debug information. The debug data, when available, is used by a service to diagnose the dump failures. You can use this option only with the -L option.
-z	Determines whether a new system dump is present. If one is present, a string that contains the size of the dump in bytes and the name of the dump device is written to a 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 you do not use any options with the sysdumpdev command, the default dump devices are used.

Security

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

Attention RBAC users: This command can perform privileged operations. Only privileged users can run privileged operations. For more information about authorizations and privileges, see Privileged Command Database in Security. For a list of privileges and the authorizations that are associated with this command, see the lssecattr command or the getcmdattr subcommand.

Error Codes

Note: A nonzero dump status indicates a failed dump. The following values are the possible dump status values and their corresponding light-emitting diode (LED) values:

Table 1. Dump status values
Dump status	Description	LED value
0	Dump completed successfully	0C0
-1	No dump device defined	0C8
-2	Dump device too small	0C4
-3	Dump crashed or did not start	0C5
-4	I/O error	0C1

Examples

Enter the following command to display the current dump device settings:
```
sysdumpdev -l
```
For information about the types of dump that the sysdumpdev command shows, see -l option.
Enter the following command to designate a logical volume hd7 as the primary dump device:
```
sysdumpdev -p /dev/hd7
```
Enter the following command to designate a tape device rmt0 as the secondary dump device:
```
sysdumpdev -s /dev/rmt0
```
Enter the following command to display the information from the previous dump invocation:
```
sysdumpdev -L
```
Enter the following command to permanently change the database object for the primary dump device to /dev/newdisk1:
```
sysdumpdev -P -p /dev/newdisk1
```
Enter the following command to determine whether a new system dump exists:
```
sysdumpdev -z
```
if a system dump occurs recently, an output that is similar to the following screen is displayed:
```
4537344 /dev/hd7
```
Enter the following command to specify the directory that a dump is copied to after a system crash, if the dump device is /dev/hd6:
```
sysdumpdev -d /tmp/dump
```
This attempt to copy the dump from the /dev/hd6 file to the /tmp/dump file after a system crash. If an error occurs during the copy, the system continues to boot and the dump is lost.
Enter the following command to specify the directory that a dump is copied to after a system crash, if the dump device is /dev/hd6:
```
sysdumpdev -D /tmp/dump
```
The command attempts to copy the dump from the /dev/hd6 directory to the /tmp/dump directory after a crash. If the copy fails, you are prompted with a menu. You can copy the dump manually to some external media through this menu.
Enter the following command to scan a dump device for a dump:
```
sysdumpdev -L -S /dev/hd6
```