Drive Identification Plugin

Owned by Rumena Zlatkova (Deactivated)
Last updated: Nov 21, 2023 by Bala Harish A(AC)
2 min read

Swarm supports a disk identification function that flashes an LED light next to a volume you select in the Swarm UI (or legacy Admin Console). The plugin turns on the disk light when a disk fails to mount, whether at reboot or hot-plug event. 

The Identify function is implemented as a Linux shell script daemon. When the Identify function is enabled, Swarm attempts one of several tools (sg_ses, MegaCli64, sas2ircu, sas3ircu) to turn on the identification light. If none of those tools succeed, Swarm continuously reads blocks from the selected disk to force the I/O activity disk light to flash.

  • The script is provided in the Swarm distribution: samples/genericDrivePlugin.sh 

    • In the Swarm bundle you downloaded (Swarm-VERSION-DATE.zip), expand the Storage files (Storage/Storage-VERSION-ARCH.zip).

  • The script is overridden if there is a custom value in the disk.volumeIdentifyFiles setting.

Best Practice

Use the generic plugin and remove any disk.volumeIdentifyFiles value from your configuration files.

Disk Light Customization

Integrators or hardware vendors with knowledge of manufacturer-specific methods for flashing disk light may substitute an alternative method using the plugin disk identification API. 

To customize disk light script:

  1. Open the Swarm software distribution and navigate to the samples directory.

  2. In the directory, copy the genericDrivePlugin.sh script to a new directory.

  3. Rename the script with a unique name that does not contain any periods or special characters.

  4. Open the script and modify the identifyOn() and identifyOff() functions as required to implement an alternate disk light identification mechanism.

  5. Archive (tar) and compress (gzip) the script and any other required custom files.

  6. Deploy the script.

  7. Place the tar file on an HTTP server or Swarm USB drive.

  8. Update the disk.volumeIdentifyFiles setting to point to the location of your tar file.

Disk Light API

These are the key functions in the generic script:

identifyOn()

Turns on the disk identification light.

identifyOff()

Turns off the disk identification light.

_monitorAndInitiate()

Polls for a disk status file and initiates identification by spawning _identifyOn().

_identifyOn()

Spawned as a process when identification is turned on by Swarm for a volume (for example, one process per volume). It calls the _identifyOn() function and then waits for identify to get turned back off by Swarm so it can call the _identifyOff() function.



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