diff options
| -rw-r--r-- | swift/common/ring/builder.py | 31 | ||||
| -rw-r--r-- | test/unit/common/ring/test_builder.py | 34 |
2 files changed, 61 insertions, 4 deletions
diff --git a/swift/common/ring/builder.py b/swift/common/ring/builder.py index f3096f6e0..225916ce8 100644 --- a/swift/common/ring/builder.py +++ b/swift/common/ring/builder.py @@ -643,6 +643,26 @@ class RingBuilder(object): self._last_part_moves[part] = 0xff self._last_part_moves_epoch = int(time()) + def _get_available_parts(self): + """ + Returns a tuple (wanted_parts_total, dict of (tier: available parts in + other tiers) for all tiers in the ring. + + Devices that have too much partitions (negative parts_wanted) are + ignored, otherwise the sum of all parts_wanted is 0 +/- rounding + errors. + + """ + wanted_parts_total = 0 + wanted_parts_for_tier = {} + for dev in self._iter_devs(): + wanted_parts_total += max(0, dev['parts_wanted']) + for tier in tiers_for_dev(dev): + if tier not in wanted_parts_for_tier: + wanted_parts_for_tier[tier] = 0 + wanted_parts_for_tier[tier] += max(0, dev['parts_wanted']) + return (wanted_parts_total, wanted_parts_for_tier) + def _gather_reassign_parts(self): """ Returns a list of (partition, replicas) pairs to be reassigned by @@ -671,6 +691,9 @@ class RingBuilder(object): # currently sufficient spread out across the cluster. spread_out_parts = defaultdict(list) max_allowed_replicas = self._build_max_replicas_by_tier() + wanted_parts_total, wanted_parts_for_tier = \ + self._get_available_parts() + moved_parts = 0 for part in xrange(self.parts): # Only move one replica at a time if possible. if part in removed_dev_parts: @@ -701,14 +724,20 @@ class RingBuilder(object): rep_at_tier = 0 if tier in replicas_at_tier: rep_at_tier = replicas_at_tier[tier] + # Only allowing parts to be gathered if + # there are wanted parts on other tiers + available_parts_for_tier = wanted_parts_total - \ + wanted_parts_for_tier[tier] - moved_parts if (rep_at_tier > max_allowed_replicas[tier] and self._last_part_moves[part] >= - self.min_part_hours): + self.min_part_hours and + available_parts_for_tier > 0): self._last_part_moves[part] = 0 spread_out_parts[part].append(replica) dev['parts_wanted'] += 1 dev['parts'] -= 1 removed_replica = True + moved_parts += 1 break if removed_replica: if dev['id'] not in tfd: diff --git a/test/unit/common/ring/test_builder.py b/test/unit/common/ring/test_builder.py index 6476b4cf8..3848725ba 100644 --- a/test/unit/common/ring/test_builder.py +++ b/test/unit/common/ring/test_builder.py @@ -19,6 +19,7 @@ import os import unittest import cPickle as pickle from collections import defaultdict +from math import ceil from tempfile import mkdtemp from shutil import rmtree @@ -718,9 +719,7 @@ class TestRingBuilder(unittest.TestCase): population_by_region = self._get_population_by_region(rb) self.assertEquals(population_by_region, {0: 682, 1: 86}) - # Rebalancing will reassign 143 of the partitions, which is ~1/5 - # of the total amount of partitions (3*256) - self.assertEqual(143, changed_parts) + self.assertEqual(87, changed_parts) # and since there's not enough room, subsequent rebalances will not # cause additional assignments to r1 @@ -744,6 +743,35 @@ class TestRingBuilder(unittest.TestCase): population_by_region = self._get_population_by_region(rb) self.assertEquals(population_by_region, {0: 512, 1: 256}) + def test_avoid_tier_change_new_region(self): + rb = ring.RingBuilder(8, 3, 1) + for i in range(5): + rb.add_dev({'id': i, 'region': 0, 'zone': 0, 'weight': 100, + 'ip': '127.0.0.1', 'port': i, 'device': 'sda1'}) + rb.rebalance(seed=2) + + # Add a new device in new region to a balanced ring + rb.add_dev({'id': 5, 'region': 1, 'zone': 0, 'weight': 0, + 'ip': '127.0.0.5', 'port': 10000, 'device': 'sda1'}) + + # Increase the weight of region 1 slowly + moved_partitions = [] + for weight in range(0, 101, 10): + rb.set_dev_weight(5, weight) + rb.pretend_min_part_hours_passed() + changed_parts, _balance = rb.rebalance(seed=2) + moved_partitions.append(changed_parts) + # Ensure that the second region has enough partitions + # Otherwise there will be replicas at risk + min_parts_for_r1 = ceil(weight / (500.0 + weight) * 768) + parts_for_r1 = self._get_population_by_region(rb).get(1, 0) + self.assertEqual(min_parts_for_r1, parts_for_r1) + + # Number of partitions moved on each rebalance + # 10/510 * 768 ~ 15.06 -> move at least 15 partitions in first step + ref = [0, 17, 16, 16, 14, 15, 13, 13, 12, 12, 14] + self.assertEqual(ref, moved_partitions) + def test_set_replicas_increase(self): rb = ring.RingBuilder(8, 2, 0) rb.add_dev({'id': 0, 'region': 0, 'zone': 0, 'weight': 1, |