Which command serves to list all available VDO devices on the system?

The command that effectively lists all available VDO (Virtual Data Optimizer) devices on a system is the one that is specifically designed for that purpose, which is "vdo list." This command is part of the VDO utility suite, which is focused on managing VDO volumes and their associated resources.

When you run this command, it provides a clear and concise output of all the VDO devices configured on the system, including details about their status, size, and other pertinent information. This explicit functionality is what distinguishes it as the correct command for the task of listing VDO devices.

In contrast, other commands such as "vdo devices," "vdo status," and "lsblk" do not serve the same functionality. While "lsblk" can show block devices on the system including VDO devices, it does not specifically focus on VDOs and may include unrelated block devices, making it less effective for this particular requirement. Understanding the specific commands pertinent to VDO management is essential for correct system administration and effective use of these tools.