README.md

   1 **mdadm** is a utility used to create and manage **software RAID** devices implemented through
   2 **Multiple devices driver (MD)** in kernel. It supports following RAID metadata formats:
   3
   4 * [Linux native RAID](https://raid.wiki.kernel.org/index.php/RAID_superblock_formats):
   5
   6   Known as **native** or **native RAID**. First and default metadata format. Metadata management
   7   is implemented in **MD driver**.
   8
   9 * Matrix Storage Manager Support (no reference, metadata format documentation is proprietary).
  10
  11   Known as **IMSM**. Metadata format developed and maintained by **Intel®** as a part of **VROC**
  12   solution. There are some functional differences between **native** and **imsm**. The most
  13   important difference is that the metadata is managed from userspace.
  14
  15   **CAUTION:** **imsm** is compatible with **Intel RST**, however it is not officially supported.
  16   You are using it on your own risk.
  17
  18 * [Common RAID DDF Specification Revision](https://www.snia.org/sites/default/files/SNIA_DDF_Technical_Position_v2.0.pdf)
  19
  20     **IMPORTANT:** DDF is in **maintenance only** mode. There is no active development around it.
  21     Please do not use it in new solutions.
  22
  23 # How to Contribute
  24
  25  **mdadm** is hosted on [kernel.org](https://kernel.org/). You can access repository
  26 [here](https://git.kernel.org/pub/scm/utils/mdadm/mdadm.git).
  27
  28 It is maintained similarly to kernel, using *mailing list*. Patches must be send through email.
  29 Please familiarize with general kernel
  30 [submitting patches](https://www.kernel.org/doc/html/v4.17/process/submitting-patches.html)
  31 documentation. Formatting, tags and commit message guidelines applies to **mdadm**.
  32
  33 ## Sending patches step-by-step
  34
  35 To maximize change of patches being taken, follow this instruction when submitting:
  36
  37 1. Create possibly logically separated commits and generate patches:
  38
  39    Use ``git format-patch --cover-letter --signoff -v <nr>`` to create patches:
  40    * ``--cover-letter`` can be skipped if it is only one patch;
  41    * ``--signoff`` adds sign-off tag;
  42    * ``-v <nr>`` indicates review revision number, sender should increment it before resending.
  43
  44 2. Check style of every patch with kernel
  45    [checkpatch](https://docs.kernel.org/dev-tools/checkpatch.html) script:
  46
  47    It is important to keep same coding style that is why in **mdadm**
  48    [kernel coding style](https://www.kernel.org/doc/html/v4.10/process/coding-style.html)
  49    is preferred. ``checkpath --no-tree <patch_file>`` can be used to verify patches.
  50    Following checkpatch issues can be ignored:
  51    - New typedefs.
  52    - comparing with *True/False*.
  53    - kernel *MAINTAINERS* file warning.
  54    - *extern* keyword in headers.
  55
  56 3. Send patches using ``git send-mail --to=linux-raid@vger.kernel.org <cover-letter> <patch1> <patch2> (...)``
  57
  58 # Maintainers
  59
  60 It is good practice to add **mdadm maintainers** to recipients for patches:
  61
  62 - Jes Sorensen <jes@trained-monkey.org>;
  63 - Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>;
  64
  65 Adding **MD maintainers** could be reasonable, especially if patches may affect MD driver:
  66
  67 - Song Liu <song@kernel.org>;
  68 - Yu Kuai <yukuai3@huawei.com>;
  69
  70 # Reviewers
  71
  72 **mdadm** utility is not part of kernel tree, so there is no certificated *Reviewers* list. Everyone
  73 can comment on mailing list, last decision (and merging) belongs to maintainers.
  74
  75 # Minimal supported kernel version
  76
  77 We do not support kernel versions below **v3.10**. Please be aware that maintainers may remove
  78 workarounds and fixes for legacy issues.
  79
  80 # License
  81
  82 It is released under the terms of the **GNU General Public License version 2** as published
  83 by the **Free Software Foundation**.