mdadm/TODO

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- add 'name' field to metadata type and use it.
- use validate_geometry more
- metadata should be able to check/reject bitmap stuff.
DDF:
Three new metadata types:
ddf - used only to create a container.
ddf-bvd - used to create an array in a container
ddf-svd - used to create a secondary array from bvds.
Usage:
mdadm -C /dev/ddf1 /dev/sd[abcdef]
mdadm -C /dev/md1 -e ddf /dev/sd[a-f]
mdadm -C /dev/md1 -l container /dev/sd[a-f]
Each of these create a new ddf container using all those
devices. The name 'ddf*' signals that ddf metadata should be used.
'-e ddf' only supports one level - 'container'. 'container' is only
supported by ddf.
mdadm -C /dev/md1 -l0 -n4 /dev/ddf1 # or maybe not ???
mdadm -C /dev/md1 -l1 -n2 /dev/sda /dev/sdb
If exactly one device is given, and it is a container, we select
devices from that container.
If devices are given that are already in use, they must be in use by
a container, and the array is created in the container.
If devices given are bvds, we slip under the hood to make
the svd arrays.
mdadm -A /dev/ddf ......
base drives make a container. Anything in that container is started
auto-read-only.
if /dev/ddf is already assembled, we assemble bvds and svds inside it.
2005-dec-20
Want an incremental assembly mode to work nicely with udev.
Core usage would be something like
mdadm --incr-assemble /dev/newdevice
This would
- examine the device to determine uuid etc.
- look for a match in /etc/mdadm.conf, abort if not found
- find that device and collect current contents
- perform an 'assemble' analysis to make sure we have the best set of devices.
- remove or add devices as appropriate
- possibly start the array if it was complete
Other usages could involve
- specify which array to auto-add to.
This requires an existing array for uuid matching... is there any point?
-
2004-june-02
* Don't print 'errors' flag, it is meaningless. DONE
* Handle new superblock format
* create device file on demand, particularly partitionable devices. DONE
BUT figure a way to create the partition devices.
auto=partN
* Use Event: interface to listen for events. DONE, untested
* Make sure mdadm -As can assemble multi-level RAIDs ok.
* --build to build raid1 or multipath arrays
clean or not ???
----------------------------------------------------------------------------
* mdadm --monitor to monitor failed multipath paths and re-instate them.
* Maybe make "--help" fit in 80x24 and have a --long-help with more info. DONE
* maybe "missing" instead of <bold>missing</> in doco DONE
* possibly wait for resync to start, or even finish while assembling.- NO
* -Db should have a devices= entry if possible. - DONE
* when assembling multipath arrays, ignore any error indicators. - DONE
* rationalise --monitor usage:
mdadm --monitor
doesn't do as expected. DONE
* --assemble could have a --update option. - DONE
following word can be:
sparc2.2
super-minor
* mdadm /dev/md11, where md11 is raid0 can segfault, particularly when looking in the
[UU_UUU] string ... which doesn't exist !
It should be more sensible. DONE
Example:
from Raimund Sacherer <raimund.sacherer@ngit.at>
mke2fs -m0 -q /dev/ram1 300
mount -n -t ext2 /dev/ram1 /tmp
echo DEVICE /dev/[sh]* >> /tmp/mdadm.conf
mdadm -Esb /dev/[sh]* 2>/dev/null >> /tmp/mdadm.conf
mdadm -ARsc /tmp/mdadm.conf
umount /tmp
?? Allow -S /dev/md? - current complains subsequent not a/d/r - DONE
* new "Query" mode to subsume --detail and --examine.
--query or -Q, takes a device and tells if it is an MD device,
and also tells in a raid superblock is found.
DONE
* write mdstat.c to parse /proc/mdstat file
Build list of arrays: name, rebuild-percent
DONE
* parse /proc/partitions and map major/minor into /dev/* names,
and use that for default DEVICE list ????
* --detail --scan to read /proc/mdstat, and then iterate over these,
but assume --brief. --verbose can override
check each subdevice to see if it is in conf_get_devs.
Warn if not.
DONE, but don't warn yet...
* Support multipath ... maybe...
maybe DONE
* --follow to syslog
* --follow to move spares around DONE
* --follow to notice other events: DONE
rebuild started
spare activated
spare removed
spare added
------------------------------------
- --examine --scan scans all drives and build an mdadm.conf file DONE
- check superblock checksum in examine DONE
- report "chunk" or "rounding" depending on raid level DONE
- report "linear" instead of "-1" for raid level DONE
- decode ayout depending on raid level DONE
- --verbose and --force flags. DONE
- set md_minor, *_disks for Create - DONE
- for create raid5, how to choose between
all working, but not insync
one missing, one spare, insync DONE (--force)
- and for raid1 - some failed drives... (missing)
- when RUN_ARRAY, make sure *_disks counts are right
- get --detail to extract extra stuff from superblock,
like uuid DONE
- --detail --brief to give a config file line DONE
- parse config file. DONE
- test...
- when --assemble --scan, if an underlying device is an md device,
then try to assemble that device first.
- mdadm -S /dev/md0 /dev/md1 gives internal error FIXED
- mdadm --detail --scan print summary of what it can find? DONE
---------
Assemble doesn't add spares. - DONE
Create to allow "missing" name for devices.
Create to accept "--force" for do exactly what is requested
- get Assemble to upgrade devices if force flag.
ARRAY lines in config file to have super_minor=n
ARRAY lines in config file to have device=pattern, and only accept
those devices
If UUID given, insist on that
If not, but super_minor given, require all found with that minor
to have same uuid
If only device given, all valid supers on those devices must have
same uuid
allow /dev/mdX as first argument before any options
Possible --dry-run option for create and assemble--force
Assemble to check that all devices mentioned in superblock
are present.
New mode: --Monitor (or --Follow)
Periodically check status of all arrays (listed in config file).
Log every event and apparent cause - or differences
Email and alert - or run a program - for important events
Move spares around if necessary.
An Array line can have a spare-group= field that indicates that
the array shares spares with other arrays with the same
spare-group name.
If an array has a failed and no spares, then check all other
arrays in the spare group. If one has no failures and a spare,
then consider that spare.
Choose the smallest considered spare that is large enough.
If there is one, then hot-remove it from it's home, and
hot-add it to the array in question.
--mail-to address
--alert-handler program
Will also extract information from /proc/mdstat if present,
and consider 20% marks in rebuild as events.
Events are:
drive fails - causes mail to be sent
rebuild started
spare activated
spare removed
spare added