1.3. DM-Multipath Components

Table 1.1, “DM-Multipath Components”. describes the components of DM-Multipath.

Table 1.1. DM-Multipath Components
Component	Description
`dm-multipath` kernel module	Reroutes I/O and supports failover for paths and path groups.
`multipath` command	Lists and configures multipath devices. Normally started up with `/etc/rc.sysinit`, it can also be started up by a `udev` program whenever a block device is added or it can be run by the `initramfs` file system.
`multipathd` daemon	Monitors paths; as paths fail and come back, it may initiate path group switches. Provides for interactive changes to multipath devices. This must be restarted for any changes to the `/etc/multipath.conf` file.
`kpartx` command	Creates device mapper devices for the partitions on a device It is necessary to use this command for DOS-based partitions with DM-MP. The `kpartx` is provided in its own package, but the `device-mapper-multipath` package depends on it.