def backup_guard_recurse(pool, class_nr):
"""Recurse version tower of hanoi backup rotation scheme for ZFS:
http://en.wikipedia.org/wiki/Backup_rotation_scheme#Tower_of_Hanoi
Snapshots are taken atomically, so that all recursive snapshots corre-
spond to the same moment in time.
:param fs: zpool name to backup (snapshot make also for all child zfs)
:type fs: str
:param class_nr: number of class used for rotation
:type class_nr: int
:raises: zfswrapper.ZfsException
"""
# tag for new snapshot
snp_tag = _gen_snapshot_tag()
unknown_label = 'unknown'
unknown_control_nr = 'X'
# make new recursive snapshot - if problem ZfsException is throw
zfs.zfs_snapshot(fs=pool, tag=snp_tag, recurse=True,
properties={_backup_property:unknown_label, _backup_control_nr:unknown_control_nr})
# get all filesystem given pool
all_fs = zfs.zfs_list(fs=pool, types='filesystem') or []
for fs in all_fs:
print 'fs', fs
## Note: you can set class_num per filesystem, exclude some zfs filesystems, e.g. pool
# get all snapshots given fs
fs_snapshots = zfs.zfs_list(fs=fs, types='snapshot') or []
# get list of snapshots and properties sorted by creation time. First is allready taken snapshot.
srt_snapshots = _get_current_hanoi_state(fs, fs_snapshots)[1:]
# get control number - useful for debuging and checking hanoi rotation scheme
_hanoi_builder(fs, snp_tag, class_nr, srt_snapshots, recurse=True)
def _hanoi_builder(fs, tag, class_nr, srt_snapshots, recurse=False):
"""Help function, take care for hanoi status
:raises: zfswrapper.ZfsException
"""
class_list = _get_class_list(class_nr) #e.g. ['A', 'B', 'C', 'D', 'E']
modulov = 2**(class_nr-1) #useful to create control number
next_control_nr = _get_next_control_number(srt_snapshots, modulov)
for ptr in range(0, class_nr):
# last must be replaced anyway; snapshot has proper class
last_class = (ptr == class_nr-1)
has_proper_class = False
if len(srt_snapshots) > ptr:
has_proper_class = (srt_snapshots[ptr][_backup_property] == class_list[ptr])
if not last_class and has_proper_class:
continue
else:
# Hanoi rotation method has the drawback of overwriting
# the very first backup (day 1 of the cycle) after only two days.
# However, this can easily be overcome by starting
# on the last day of a cycle.
class_label = class_list[ptr]
if not srt_snapshots:
class_label = class_list[-1]
# get all old snapshots same class
old_snapshot = filter(lambda x: x[_backup_property]==class_label, srt_snapshots)
print "to create: {'%s': '%s', '%s': '%s'}" % (_backup_property, class_label, _backup_control_nr, next_control_nr)
if recurse:
snp_already_taken = '%s@%s' % (fs, tag)
# mark already taken snapshot with proper class and control_nr - if problem ZfsException is throw
zfs.zfs_set(snp_already_taken, _backup_control_nr, next_control_nr)
zfs.zfs_set(snp_already_taken, _backup_property, class_label)
else:
# make new snapshot - if problem ZfsException is throw
zfs.zfs_snapshot(fs, tag, properties={_backup_property:class_label, _backup_control_nr:next_control_nr})
# delete old snapshots same class, only if new snapshot was taken - if probelm ZfsException is throw
for old in old_snapshot:
print 'to destroy:', old
zfs.zfs_destroy(old['name'])
# job done
break
def replication_simulator():
"""Demo - send and receive snapshot.
.. warning::
recv_fs can't exist on recv_host, otherwise error is risen
"""
send_fs = "galaxy01/fleet11"
send_tag = "satellite-red01"
to_send = "%s@%s" % (send_fs, send_tag)
# create local snapshot to teleport if not exist
if not zfs.zfs_list(fs=to_send):
zfs.zfs_snapshot(send_fs, send_tag)
# Remote repl. - using ssh
recv_fs = "galaxy_slave01/fleet11_alfa"
# recv_fs = 'galaxy_slave01/fleet11_beta'
zfs.zfs_teleport_snapshot(to_send, recv_fs, recv_host="zepto")
# Local repl.
recv_fs = "galaxy02/fleet11_alfa"
# recv_fs = 'galaxy02/fleet11_beta'
zfs.zfs_teleport_snapshot(to_send, recv_fs)
