Documentation/admin-guide/device-mapper/dm-raid.rst

Source file repositories/reference/linux-study-clean/Documentation/admin-guide/device-mapper/dm-raid.rst

File Facts

System
Linux kernel
Corpus path
Documentation/admin-guide/device-mapper/dm-raid.rst
Extension
.rst
Size
20494 bytes
Lines
490
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

=======
dm-raid
=======

The device-mapper RAID (dm-raid) target provides a bridge from DM to MD.
It allows the MD RAID drivers to be accessed using a device-mapper
interface.


Mapping Table Interface
-----------------------
The target is named "raid" and it accepts the following parameters::

  <raid_type> <#raid_params> <raid_params> \
    <#raid_devs> <metadata_dev0> <dev0> [.. <metadata_devN> <devN>]

<raid_type>:

  ============= ===============================================================
  raid0		RAID0 striping (no resilience)
  raid1		RAID1 mirroring
  raid4		RAID4 with dedicated last parity disk
  raid5_n 	RAID5 with dedicated last parity disk supporting takeover from/to raid1
		Same as raid4

		- Transitory layout for takeover from/to raid1
  raid5_la	RAID5 left asymmetric

		- rotating parity 0 with data continuation
  raid5_ra	RAID5 right asymmetric

		- rotating parity N with data continuation
  raid5_ls	RAID5 left symmetric

		- rotating parity 0 with data restart
  raid5_rs 	RAID5 right symmetric

		- rotating parity N with data restart
  raid6_zr	RAID6 zero restart

		- rotating parity zero (left-to-right) with data restart
  raid6_nr	RAID6 N restart

		- rotating parity N (right-to-left) with data restart
  raid6_nc	RAID6 N continue

		- rotating parity N (right-to-left) with data continuation
  raid6_n_6	RAID6 with dedicate parity disks

		- parity and Q-syndrome on the last 2 disks;
		  layout for takeover from/to raid0/raid4/raid5_n
  raid6_la_6	Same as "raid_la" plus dedicated last Q-syndrome disk supporting takeover from/to raid5

		- layout for takeover from raid5_la from/to raid6
  raid6_ra_6	Same as "raid5_ra" dedicated last Q-syndrome disk

		- layout for takeover from raid5_ra from/to raid6
  raid6_ls_6	Same as "raid5_ls" dedicated last Q-syndrome disk

		- layout for takeover from raid5_ls from/to raid6
  raid6_rs_6	Same as "raid5_rs" dedicated last Q-syndrome disk

		- layout for takeover from raid5_rs from/to raid6
  raid10        Various RAID10 inspired algorithms chosen by additional params
		(see raid10_format and raid10_copies below)

		- RAID10: Striped Mirrors (aka 'Striping on top of mirrors')
		- RAID1E: Integrated Adjacent Stripe Mirroring
		- RAID1E: Integrated Offset Stripe Mirroring
		- and other similar RAID10 variants

Annotation

Implementation Notes