mdadm is a utility used to create and manage software RAID devices implemented through Multiple devices driver (MD) in kernel. It supports following RAID metadata formats:
Known as native or native RAID. First and default metadata format. Metadata management is implemented in MD driver.
Matrix Storage Manager Support (no reference, metadata format documentation is proprietary).
Known as IMSM. Metadata format developed and maintained by Intel® as a part of VROC solution. There are some functional differences between native and imsm. The most important difference is that the metadata is managed from userspace.
CAUTION: imsm is compatible with Intel RST, however it is not officially supported. You are using it on your own risk.
Common RAID DDF Specification Revision
IMPORTANT: DDF is in maintenance only mode. There is no active development around it. Please do not use it in new solutions.
mdadm is hosted on kernel.org. You can access repository here.
It is maintained similarly to kernel, using mailing list. Patches must be send through email. Please familiarize with general kernel submitting patches documentation. Formatting, tags and commit message guidelines applies to mdadm.
To maximize change of patches being taken, follow this instruction when submitting:
Create possibly logically separated commits and generate patches:
Use git format-patch --cover-letter --signoff -v <nr> to create patches:
--cover-letter can be skipped if it is only one patch;--signoff adds sign-off tag;-v <nr> indicates review revision number, sender should increment it before resending.Check style of every patch with kernel checkpatch script:
It is important to keep same coding style that is why in mdadm kernel coding style is preferred. checkpath --no-tree <patch_file> can be used to verify patches. Following checkpatch issues can be ignored:
Send patches using git send-mail --to=linux-raid@vger.kernel.org <cover-letter> <patch1> <patch2> (...)
It is good practice to add mdadm maintainers to recipients for patches:
Adding MD maintainers could be reasonable, especially if patches may affect MD driver:
mdadm utility is not part of kernel tree, so there is no certificated Reviewers list. Everyone can comment on mailing list, last decision (and merging) belongs to maintainers.
We do not support kernel versions below v3.10. Please be aware that maintainers may remove workarounds and fixes for legacy issues.
It is released under the terms of the GNU General Public License version 2 as published by the Free Software Foundation.