Manpage of MDADM.CONF


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mdadm.conf - configuration for management of Software Raid with mdadm  




mdadm is a tool for creating, managing, and monitoring RAID devices using the md driver in Linux.

Some common tasks, such as assembling all arrays, can be simplified by describing the devices and array in this configuation file.



The file should be seen as a collection of words separated by white space (space, tab, or newline). Any word that beings with a hash sign (#) starts a comment and that word together with the remainder of the line are ignored.

Any line that start with white space (space or tab) is treated as though it were a continuation of the previous line.

Empty lines are ignored, but otherwise each (non continuation) line must start with a keyword as listed below. The key words are case insensitve and can be abbreviated to 3 characters.

The keywords are:

A device line lists the devices (whole devices or partitions) that might contain a component of an MD array. When looking for the components of an array, mdadm will scan these devices and no others.

The device line may contain a number of different devices (separated by spaces) and each device name can contain wild cards as defined by glob(7).

Also, there may be several device lines present in the file.

For example:

DEVICE /dev/hda* /dev/hdc*
DEV /dev/sd*
DEVICE /dev/discs/disc*/disc

The ARRAY lines identify actual arrays. The second word on the line should be the name of the device where the array is normally assembled, such as /dev/md1. Subsequent words identify the array. If multiple identities are given, then the array must match ALL identities to be considered a match. Each identity word has a tag, and equals sign, and some value. The options are:

The value should be a 128 bit uuid in hexadecimal, with punctuation interspersed if desired. This must match the uuid stored in the superblock.
The value is an integer which indicates the minor number that was stored in the superblock when the array was created. When an array is created as /dev/mdX, then the minor number X is stored.
The value is a comma separated list of device names. Precisely these devices will be used to assemble the array. Note that the devices listed there must also be listed on a DEVICE line.
The value is a raid level. This is not normally used to identify an array, but is supported so that the output of

mdadm --examine --scan

can be use directly in the configuration file.

The value is the number of disks in a complete active array. As with level= this is mainly for compatibility with the output of

mdadm --examine --scan.



mdadm(8), md(4).




This document was created by man2html, using the manual pages.
Time: 04:53:57 GMT, February 26, 2024