ServerBuddies Support Blog

Scanning for Block Devices

You can scan for block devices that may be used as physical volumes with the lvmdiskscan
command, as shown in the following example.

The Linux system identifies hardware devices as special files, called device files. There are three
different classifications of device files:

? Character
? Block
? Network

Character device files are for devices that can only handle data one character at a time. Most types
of modems and terminals are created as character files. Block files are for devices that can handle
data in large blocks at a time, such as disk drives.

The network file types are used for devices that use packets to send and receive data. This includes network cards and a special loopback device that allows the Linux system to communicate with itself using common network programming protocols.

Scanning for Block Devices

You can scan for block devices that may be used as physical volumes with the lvmdiskscan command, as shown in the following example.

lvmdiskscan scans all SCSI, (E)IDE disks, multiple devices and a bunch of other block devices in the system looking for LVM physical volumes. The size reported is the real device size. Define a filter in lvm.conf(5) to restrict the scan to avoid a CD ROM, for example.

If run as a user then.