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ironic-specs
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Merge "Add details on target_raid_config for Software RAID support"

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Zuul 2019-04-15 09:45:43 +00:00 committed by Gerrit Code Review
parent 43eb3c0b56 6053cae0cd
commit 997e184cc9
1 changed files with 42 additions and 3 deletions
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specs/approved/software-raid.rst
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@ -75,10 +75,49 @@ configurations: a RAID-1 holder device can look like a standalone disk and does
not require the bootloader to have any knowledge or capabilities to understand
more complex RAID configurations.
In order to signal that a software RAID configuration is indeed desired (and
to protect from a situation where a software RAID is set up accidentally
when the configuration passed via the ``target_raid_config`` was meant for a
hardware RAID setup, for instance), the ``controller`` property of all of the
logical disks needs to be set to ``software``. Without this setting, the
software RAID code in the GenericHardwareManager of the IPA will ignore the
given ``target_raid_config``. If it is set on only one of the logical drives,
the validation code will raise an error.
The ``controller`` property set to ``software`` will also be used by the
conductor to identify a software RAID and trigger the required installation of
the bootloader. While whole-disk images are expected to come with a bootloader
configuration as part of the image, for software RAIDs in the current design
the image will not be at the start of a real disk, but inside the first
partition on top of a software RAID-1. The bootloader must hence be explicitly
installed onto the underlying holder disks, and this property will indicate
when to do this.
An example of a valid software RAID configuration would hence look like::
{
"logical_disks": [
{
"size_gb": 100,
"raid_level": "1",
"controller": "software"
},
{
"size_gb": "MAX",
"raid_level": "0",
"controller": "software"
}
]
}
Support for more than one RAID-N, support for the selection of a subset of
drives to act as holder devices, as well as support to partition the created
RAID-N device are left for follow-up enhancements and beyond the scope of
this specification.
drives to act as holder devices, support for simultaneous software and
hardware RAID devices as well as support to partition the created RAID-N
device are left for follow-up enhancements and beyond the scope of this
specification.
Also, there is currently no support for partition images, only whole disk
images are supported.
A first prototype very close to the proposal is available from [2][3][4].