dmeventd - Linux

Overview

dmeventd is a daemon that monitors Device Mapper Event (DME) devices and controls their corresponding DME targets. It provides an interface for applications to create, destroy, and modify DME devices and targets, allowing for dynamic management of disk and storage configurations.

Syntax

dmeventd [options]

Options/Flags

  • -f, –foreground
    Run in the foreground without daemonizing.
  • -h, –help
    Display command help and exit.
  • -l, –log-level
    Set the logging level (error, info, debug). Defaults to info.
  • -p, –pid-file
    Specify the path to the PID file. Defaults to /var/run/dmeventd.pid.
  • -s, –socket
    Specify the UNIX socket path to listen on for client connections. Defaults to /var/run/dmeventd.sock.

Examples

  1. Create a DME device and target:
dmeventd --create-device /dev/dm-test --create-target /dev/sdc1
  1. Destroy a DME device and target:
dmeventd --destroy-device /dev/dm-test --destroy-target /dev/sdc1
  1. Modify a DME target:
dmeventd --set-target /dev/dm-test --offset 1024 --size 102400

Common Issues

  1. dmeventd fails to start: Check if the specified UNIX socket file exists and has the proper permissions.
  2. DME devices or targets cannot be created: Ensure that the kernel module dme is loaded and the necessary device drivers are installed.

Integration

dmeventd can be integrated with other commands and tools for advanced management tasks, such as:

  • lvm: Use dmeventd to manage logical volumes on top of DME targets.
  • cryptsetup: Encrypt DME targets using cryptsetup for secure data storage.

Related Commands

  • dmsetup: Manage Device Mapper devices directly.
  • pvcreate, vgcreate, lvcreate: Create and manage logical volumes using the LVM stack.