def mdremove(mdname):
# check if md exists
if mdname not in get_mdnames():
raise errors.MDNotFoundError(
'Error while removing md: md %s not found' % mdname)
# FIXME: The issue faced was quiet hard to reproduce and to figure out the
# root cause. For unknown reason already removed md device is
# unexpectedly returning back after a while from time to time making
# new md device creation to fail.
# Still the actual reason of its failure is unknown, but after a
# searching on a web a mention was found about a race in udev
# http://dev.bizo.com/2012/07/mdadm-device-or-resource-busy.html
# The article recommends to disable udev's queue entirely during md
# device manipulation which sounds rather unappropriate for our case.
# And the link to original post on mailing list suggests to execute
# `udevadm settle` before removing the md device.
# here -> http://permalink.gmane.org/gmane.linux.raid/34027
# So, what was done. `udevadm settle` calls were placed just
# before any of `mdadm` calls and the analizyng the logs was started.
# According to the manual `settle` is an option that "Watches the
# udev event queue, and exits if all current events are handled".
# That means it will wait for udev's finishing of processing the
# events. According to the logs noticeable delay had been recognized
# between `udevadm settle` and the next `mdadm` call.
# The delay was about 150-200ms or even bigger. It was appeared
# right before the `mdadm --stop` call. That just means that udev was
# too busy with events when we start to modifiy md devices hard.
# Thus `udevadm settle` is helping to avoid the later failure and
# to prevent strange behaviour of md device.
utils.udevadm_settle()
utils.execute('mdadm', '--stop', mdname, check_exit_code=[0])
utils.execute('mdadm', '--remove', mdname, check_exit_code=[0, 1])
def mdremove(mdname):
mds = mddisplay()
# check if md exists
if not filter(lambda x: x['name'] == mdname, mds):
raise errors.MDNotFoundError(
'Error while removing md: md %s not found' % mdname)
utils.execute('mdadm', '--stop', mdname, check_exit_code=[0])
utils.execute('mdadm', '--remove', mdname, check_exit_code=[0, 1])
def mdcreate(mdname, level, devices, metadata='default'):
mds = mddisplay()
# check if md device already exists
if next((x for x in mds if x['name'] == mdname), False):
raise errors.MDAlreadyExistsError(
'Error while creating md: md %s already exists' % mdname)
# check if level argument is valid
supported_levels = ('0', '1', 'raid0', 'raid1', 'stripe', 'mirror')
if level not in supported_levels:
raise errors.MDWrongSpecError('Error while creating md device: '
'level must be one of: %s' %
', '.join(supported_levels))
# check if all necessary devices exist
if not set(devices).issubset(
set([bd['device'] for bd in hu.list_block_devices(disks=False)])):
raise errors.MDNotFoundError(
'Error while creating md: at least one of devices is not found')
# check if devices are not parts of some md array
if set(devices) & set(
itertools.chain.from_iterable(md.get('devices', [])
for md in mds)):
raise errors.MDDeviceDuplicationError(
'Error while creating md: at least one of devices is '
'already in belongs to some md')
# FIXME: mdadm will ask user to continue creating if any device appears to
# be a part of raid array. Superblock zeroing helps to avoid that.
for device in devices:
mdclean(device)
utils.execute('mdadm',
'--create',
'--force',
mdname,
'-e',
metadata,
'--level=%s' % level,
'--raid-devices=%s' % len(devices),
*devices,
check_exit_code=[0])
def mdcreate(mdname, level, device, *args):
mds = mddisplay()
# check if md device already exists
if filter(lambda x: x['name'] == mdname, mds):
raise errors.MDAlreadyExistsError(
'Error while creating md: md %s already exists' % mdname)
# check if level argument is valid
supported_levels = ('0', '1', 'raid0', 'raid1', 'stripe', 'mirror')
if level not in supported_levels:
raise errors.MDWrongSpecError('Error while creating md device: '
'level must be one of: %s' %
', '.join(supported_levels))
devices = [device] + list(args)
# check if all necessary devices exist
if not set(devices).issubset(
set([bd['device'] for bd in hu.list_block_devices(disks=False)])):
raise errors.MDNotFoundError(
'Error while creating md: at least one of devices is not found')
# check if devices are not parts of some md array
if set(devices) & \
set(reduce(lambda x, y: x + y,
[md.get('devices', []) for md in mds], [])):
raise errors.MDDeviceDuplicationError(
'Error while creating md: at least one of devices is '
'already in belongs to some md')
#FIXME: mdadm will ask user to continue creating if any device appears to
# be a part of raid array. Superblock zeroing helps to avoid that.
map(mdclean, devices)
utils.execute('mdadm',
'--create',
'--force',
mdname,
'-e0.90',
'--level=%s' % level,
'--raid-devices=%s' % len(devices),
*devices,
check_exit_code=[0])
