2.1.4 is getting pretty old. There’s a DTCS deletion tweak in 2.1.5 ( https://issues.apache.org/jira/browse/CASSANDRA-8359 ) that may help you.
2.1.5 and 2.1.6 have some memory leak issues in DTCS, so go to 2.1.7 or newer
(probably 2.1.9 unless you have a compelling reason not to go to 2.1.9)
From: Venkatesh Arivazhagan
Reply-To: "user@cassandra.apache.org"
Date: Sunday, September 20, 2015 at 2:48 PM
To: "user@cassandra.apache.org"
Subject: Help with tombstones and compaction
Hi Guys,
I have a Cassandra 2.1.4 cluster with 14 nodes. I am using it primarily for
storing time series data collected via KairosDB.
The default TTL for data inserted into the column family named data_points is
12hrs. I have also set the gc_grace_seconds to 12 hrs.
In-spite of this my disk space keeps on increasing and it looks like tombstones
are never dropped.
It looks like compactions are happening on a regular basis. The SSTable count
does not seem outrageous either. It is constantly between ~10 to ~22.
Am I doing anything wrong? Is there a way to mitigate this?
Attached:
* DESC output for my keyspace
* Disk usage graph
* LiveSSTable Count graph
--------------------------------------------------------------------------------------------------------------------------
CREATE KEYSPACE kairosdb WITH replication = {'class': 'SimpleStrategy',
'replication_factor': '3'} AND durable_writes = true;
CREATE TABLE kairosdb.data_points (
key blob,
column1 blob,
value blob,
PRIMARY KEY (key, column1)
) WITH COMPACT STORAGE
AND CLUSTERING ORDER BY (column1 ASC)
AND bloom_filter_fp_chance = 0.01
AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
AND comment = ''
AND compaction = {'max_sstable_age_days': '365', 'base_time_seconds':
'3600', 'max_threshold': '32', 'timestamp_resolution': 'MILLISECONDS',
'enabled': 'true', 'tombstone_compaction_interval': '1', 'min_threshold': '4',
'tombstone_threshold': '.1', 'class':
'org.apache.cassandra.db.compaction.DateTieredCompactionStrategy'}
AND compression = {'sstable_compression':
'org.apache.cassandra.io.compress.LZ4Compressor'}
AND dclocal_read_repair_chance = 0.1
AND default_time_to_live = 43200
AND gc_grace_seconds = 43200
AND max_index_interval = 2048
AND memtable_flush_period_in_ms = 0
AND min_index_interval = 128
AND read_repair_chance = 0.1
AND speculative_retry = 'NONE';
CREATE TABLE kairosdb.row_key_index (
key blob,
column1 blob,
value blob,
PRIMARY KEY (key, column1)
) WITH COMPACT STORAGE
AND CLUSTERING ORDER BY (column1 ASC)
AND bloom_filter_fp_chance = 0.01
AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
AND comment = ''
AND compaction = {'min_threshold': '4', 'class':
'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy',
'max_threshold': '32'}
AND compression = {'sstable_compression':
'org.apache.cassandra.io.compress.LZ4Compressor'}
AND dclocal_read_repair_chance = 0.1
AND default_time_to_live = 0
AND gc_grace_seconds = 43200
AND max_index_interval = 2048
AND memtable_flush_period_in_ms = 0
AND min_index_interval = 128
AND read_repair_chance = 0.1
AND speculative_retry = 'NONE';
CREATE TABLE kairosdb.string_index (
key blob,
column1 text,
value blob,
PRIMARY KEY (key, column1)
) WITH COMPACT STORAGE
AND CLUSTERING ORDER BY (column1 ASC)
AND bloom_filter_fp_chance = 0.01
AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
AND comment = ''
AND compaction = {'min_threshold': '4', 'class':
'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy',
'max_threshold': '32'}
AND compression = {'sstable_compression':
'org.apache.cassandra.io.compress.LZ4Compressor'}
AND dclocal_read_repair_chance = 0.1
AND default_time_to_live = 0
AND gc_grace_seconds = 43200
AND max_index_interval = 2048
AND memtable_flush_period_in_ms = 0
AND min_index_interval = 128
AND read_repair_chance = 0.1
AND speculative_retry = 'NONE';
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