Commit d55f154b authored by Felix Seibert's avatar Felix Seibert
Browse files

updating documentation

parent c1ceb491
......@@ -8,14 +8,17 @@ class DataDistribution(object):
class to keep track of the osd (object storage device) locations of different folders, i.e.,
their physical location.
this class also allows to calculate a 'good' osd for new data, based on the
distribution known beforehand.
this class also allows to calculate several data distributions, e.g., mappings from folders to OSDs (each folder
gets mapped to one OSD).
"""
def __init__(self):
self.OSDs = {}
def add_new_osd(self, osd_uuid):
"""
create a new empty osd and add it to the existing OSDs.
"""
if osd_uuid in self.OSDs:
print("key: " + osd_uuid + " is already present!")
return
......@@ -23,30 +26,45 @@ class DataDistribution(object):
self.OSDs[osd_uuid] = new_osd
def add_osd(self, new_osd):
"""
add the given OSD (object) to the existing OSDs.
"""
if new_osd.uuid in self.OSDs:
print("key: " + new_osd.uuid + " is already present!")
return
self.OSDs[new_osd.uuid] = new_osd
def add_osd_list(self, osd_list):
"""
add the given list of OSDs (objects) to the existing OSDs.
"""
for osd_uuid in osd_list:
if osd_uuid not in self.OSDs:
new_osd = osd.OSD(osd_uuid)
self.OSDs[osd_uuid] = new_osd
def get_osd_list(self):
"""
get a list of all existing OSDs.
"""
osd_list = []
for osd_name in self.OSDs.keys():
osd_list.append(osd_name)
return osd_list
def get_containing_osd(self, folder_id):
"""
get the OSD containing the given folder_id, or None if the folder is not assigned to any OSD.
"""
for checked_osd in self.OSDs.values():
if checked_osd.contains_folder(folder_id):
return checked_osd
return None
def get_average_folder_size(self):
"""
get the average folder size of all folders of all OSDs.
"""
total_size = 0
total_number_of_folders = 0
for one_osd in self.OSDs.values():
......@@ -57,6 +75,9 @@ class DataDistribution(object):
return total_size / total_number_of_folders
def assign_new_osd(self, folder_id, new_osd):
"""
assign folder_id to new_osd. if folder_id already is assigned to an OSD, this old assignment is deleted.
"""
old_osd = self.get_containing_osd(folder_id)
if old_osd is None:
self.OSDs[new_osd].add_folder(folder_id, self.get_average_folder_size())
......@@ -67,6 +88,7 @@ class DataDistribution(object):
def add_folders(self, folders, osd_information=None, ratio_parameter='', random_osd_assignment=False):
"""
adds a list of folders to the data distribution.
if not specified otherwise, the assignments are calculated using the LPT algorithm.
returns a list of assignments from folders to OSDs, for which (folders) there was previously no assignment.
if the optional arguments are given, OSDs are assigned data proportionally to their ratio_parameter.
......
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