Diablo: ULLtraDIMM - CLI Managing Devices

Device Management Commands

This section describes the commands that are used to manage devices:

• online mode
• maintenance mode
• enabling TRIM
• disabling TRIM
• commit mode strategy
• device alias
• attach to group
• save device configuration

Put device in online mode

The online parameter of the device command is used to put a device in online mode after it was put in maintenance mode for certain tasks, such as formatting a device or enabling or disabling TRIM.

[root@mcs ~]# td-cli device tda --online
Device tda is already online

Put device in maintenance mode

The maintenance parameter of the device command is used to put a device in maintenance mode. Maintenance mode is required for several tasks on the device, such as formatting a device or enabling or disabling TRIM.

[root@mcs ~]# td-cli device tda --maintenance
Device tda successfully put into maintenance mode

Enable TRIM

The TRIM command enables the host to communicate to the device that blocks of data have been de-allocated. As a result, the device is able to return those blocks to the pool of available unused blocks, which enables the device to maintain a higher level of background/overhead efficiency, minimizing subsequent Write Amplification and improving performance.

TRIM is disabled on each device by default. Operating systems that do not support TRIM ignore this setting.

To enable TRIM, use the trim on parameter of the device command.

N.B. - The device must be in maintenance mode to enable TRIM

[root@mcs ~]# td-cli device tda --maintenance
Device tda successfully put into maintenance mode

[root@mcs ~]# td-cli device tda --trim on
TRIM has been turned on for device tda

[root@mcs ~]# td-cli device tda --online
Device tda successfully put into online mode

Disable TRIM

TRIM is disabled on each device by default. If TRIM has been enabled, you can disable it by using the trim off parameter of the device command.

N.B. - The device must be in maintenance mode to disable TRIM

[root@mcs ~]# td-cli device tda --maintenance
Device tda successfully put into maintenance mode

[root@mcs ~]# td-cli device tda --trim off
TRIM has been turned off for device tda

[root@mcs ~]# td-cli device tda --online
Device tda successfully put into online mode

Set commit mode

The commit mode strategy is used to specify at which point, on the path from the host memory controller to the device flash, the write is completed.

The values are normal, which is standard execution, and WriteNow, which accelerates the write acknowledgement. In both strategies, the data is secure in the case of a power failure.

[root@mcs ~]# td-cli device tda --commit WriteNow
Commit mode for tda has been succesfully set to WriteNow

[root@mcs ~]# td-cli device tda --commit normal
Commit mode for tda has been succesfully set to normal

Set device alias

A device alias is useful for substituting a user-friendly, easy to remember name for a device. The device-alias command requires the device ID and a new name to be used instead of the device ID. You can use the characters a through z, the numbers 0 through 9, and spaces for your alias. There is a character limit of 32; additional characters will be truncated.

[root@mcs ~]# td-cli device-alias tda --set ULLtraDIMM
Device alias set to ULLtraDIMM

Attach device to group

Processor affinity is set by attaching a device to a group. Device groups are used to ensure that devices are using specific CPUs. Each device must be attached to a group. A device can be migrated from one group to another by attaching it to a new group.

For more information on device groups, see: Managing Device Groups

The attach parameter of the device command is used to attach a device to a group.

[root@mcs ~]# td-cli device tdd --attach td-cpu-28
Device tdd successfully added to group td-cpu-28

Save device configuration

The "save' parameter of the host-config command is used to save current group/device configuration settings and load them automatically on startup.

If you make changes after you have run this command, you will need to run the command again for the changes to be applied on startup.

On a Linux system, you will be prompted to copy the file to a specified location, so that the saved configuration file will be loaded automatically on startup.

[root@mcs ~]# td-cli host-config --save
A teradimm.conf file has been created, please copy this into /etc/teradimm/. The configuration within this file will be loaded on system start. To change your persistant configuration please re-run this command and copy the new teradimm.conf into /etc/teradimm.