Managing RAID on Linux

Name

Manage and Miscellaneous modes

Synopsis

mdadm [options] mddevice memberdevices
mdadm mddevice [options] memberdevices
mdadm [options] memberdevices
mdadm [options]

The remaining options fall into the loosely defined categories of Manage and Miscellaneous modes. For the most part, these options work individually, but some of them can be combined to provide additional functionality. Many of these options are used on arrays, while some of them are used directly on member disks. See the Example usage section that follows for some common tasks.

Options

-Q, --query

Queries an array or member disk to determine array properties, member disk properties, or both in cases when an array is also a member disk (in a hybrid array, for example). --query displays very brief information: array size, RAID level, and status. For member disks, it displays the disk sequence instead of the array size.

-D, --detail

Prints verbose details about an active array.

-E, --examine

Prints the contents of the md superblock from a member disk. This is usually a single device, but in the case of hybrids, it can also be an array.

-b, --brief

When combined with either --detail or -examine, generates a configuration file entry for an array. When combined with --detail, an active array is queried and used to generate the configuration entry. When combined with --examine, the RAID superblock is read from a member disk and used to generate the configuration entry. In general, it’s best to use the --detail form when possible because ...