About Me
#CassandraSummit 2014
● Sr. Engineer at Pythian o Lead of Cassandra Practice
● Remote in Minnesota ● Interests
o Java, Clojure, Python dev o Data science o Information Security o Hobbyist electronics
About Pythian
#CassandraSummit 2014
Pythian is a global data outsourcing and consulting company that specializes in optimizing and managing mission-critical data systems.
Pythian blends the world’s leading data experts with advanced, secure service delivery processes to create the industry’s best standard of care for its clients.
Since its inception, Pythian has managed some of the world’s largest, most business-critical data infrastructures.
10,000 Pythian currently manages more than 10,000 systems.
350 Pythian currently employs more than 350 people in 25 countries worldwide.
1997 Pythian was founded in 1997
About Cassandra
#CassandraSummit 2014
● No Single Point of Failure
● Fault Tolerant
● Awesome properties for an operations team who does not want to get up at 3am
About Cassandra
#CassandraSummit 2014
● Nothing should be set up and forgotten about ● Easy to do with Cassandra though
o Fault tolerance on properly configured setup handles single node being down or having temp performance issues
o No back pressure on writes until there is a lot of trouble
Utilize the fault tolerance buffer
#CassandraSummit 2014
● Need to observe and react to current issues ● Predict future issues ● Divide this into two approaches o Proactive o Reactive
Proactive
#CassandraSummit 2014
● Daily & Weekly checkups to prevent, and predict problems o Capacity o Performance bottlenecks o Data Modeling issues
Reactive
#CassandraSummit 2014
● Something about best laid plans… o Hardware failures o Bugs o Malicious or Non-Malicious users
● Alarms, Pager Duty
Common element
#CassandraSummit 2014
● Data is needed o form alerts o find anomalies o trending o debugging
Metrics
#CassandraSummit 2014
● Window to the application o Bridge the gap - Coda Hale
Cassandra Environment
OpsCenter Logs
JMX CPU, Disk, Network
Nodetool JVM, GC
SOURCES
Gathering Metrics
#CassandraSummit 2014
Metrics but of course… Without context, the data is just pretty graphs
JMX
#CassandraSummit 2014
● Java Management Extensions ● Complex… very engineered ● Resources represented as objects with
attributes and operations ● Used for monitoring or as input
● The annoying gateway to metrics ○ Poor tooling - requires java ○ Slow, Memory Leaks ○ Historically and currently frustrating for ops (pre 2.0.8)
JMX
#CassandraSummit 2014
1024-65535
Init connection to port 7199 Reply with hostname:port for
RMI connection
Client (You)
Gets new hostname:port, drops old connection and attempts to connect
7199
7199
Connected!
Cassandra
JMX
#CassandraSummit 2014
● Visual o jconsole o visualvm
● Command line o jmxterm o jmxsh
● MX4J ● Jolokia
JMX
#CassandraSummit 2014
[domain]:[key]=[value],[key2]=[value2]...
JMX
#CassandraSummit 2014
[domain]:[key]=[value],[key2]=[value2]... com.pythian:site=blog,type=views,target=post1
JMX
#CassandraSummit 2014
[domain]:[key]=[value],[key2]=[value2]... com.pythian:site=blog,type=views,target=post1
JMX
#CassandraSummit 2014
[domain]:[key]=[value],[key2]=[value2]... com.pythian:site=blog,type=views,target=post1
JMX Domains
#CassandraSummit 2014
org.apache.cassandra. ● db ● internal ● net ● request
org.apache.cassandra.metrics ● db ● internal ● net ● request
JMX Beans
#CassandraSummit 2014
JMX
#CassandraSummit 2014
org.apache.cassandra.metrics :type=
● Cache ● Client ● ClientRequest ● ClientRequestMetrics ● ColumnFamily ● CommitLog ● Compaction
● DroppedMessage ● FileCache ● Keyspace ● Storage ● ThreadPools
JMX
#CassandraSummit 2014
org.apache.cassandra.metrics
type=*, scope=*, name=*,
type=ThreadPools, path=*, scope=*, name=*,
type=ColumnFamily, keyspace=*, scope=*, name=*,
type=Keyspace, keyspace=*, name=*,
Metrics
#CassandraSummit 2014
● Toolkit called metrics for metrics o By Coda Hale @ Yammer
● Easy to use ● Popular
Types of Metrics
#CassandraSummit 2014
● Gauge o instantaneous value
● Counter o number that can be incremented & decremented
● Meter o rate of events over time (1/5/15 min moving avg)
● Histogram o representation of statistical distribution
§ 50, 75, 95, 98, 99, 99.9 percentile § average, median, min, max, standard deviation
● Timer o rate of events (meter) o histogram of duration
JMX
#CassandraSummit 2014
75th percentile is 683 MICROSECONDS (75% took 683us or less)
One minute rate is 13,915 calls per SECOND
JMX
#CassandraSummit 2014
● Overwhelming at first ● Hard to tell what they mean without the source ● Moves around a lot ● Fortunately there is nodetool
Nodetool
#CassandraSummit 2014
● JMX command line wrapper ● Many options ● Operations and diagnostic procedures ● For reactive analysis
o ad hoc, spot checks
Nodetool tpstats
#CassandraSummit 2014
nodetool tpstats org.apache.cassandra.metrics:type=ThreadPools,path={internal|request|transport},scope={*},name= {ActiveTasks|PendingTasks|CompletedTasks|CurrentlyBlockedTasks|TotalBlockedTasks} Pool Name Active Pending Completed Blocked All time blocked
ReadStage 0 0 113702 0 0 RequestResponseStage 0 0 0 0 0 MutationStage 0 0 164503 0 0 ... InternalResponseStage 0 0 0 0 0 HintedHandoff 0 0 0 0 0 Message type Dropped RANGE_SLICE 0 READ_REPAIR 0 ... REQUEST_RESPONSE 0 COUNTER_MUTATION 0
Staged Event Driven Architecture
#CassandraSummit 2014
● Decomposes complex event system ● Set of stages (thread pools) ● Queue between each ● Shares a lot of pros cons as SOA
Staged Event Driven Architecture
#CassandraSummit 2014
Threads
ReadStage
x32
Clie
nt R
eque
st RequestResponse
Threads
ReadRepairStage
Threads
Messaging Service
Node 2
Node 1 Node 1
Nod
e 1
= Task
Staged Event Driven Architecture
#CassandraSummit 2014
● Its easy to overrun the processing capabilities of a stage that is not in the requests feedback loop (i.e. ReadRepairStage).
● No write back pressure
Nodetool tpstats
#CassandraSummit 2014
nodetool tpstats org.apache.cassandra.metrics:type=ThreadPools,path={internal|request|transport},scope={*},name= {ActiveTasks|PendingTasks|CompletedTasks|CurrentlyBlockedTasks|TotalBlockedTasks} Pool Name Active Pending Completed Blocked All time blocked
ReadStage 0 0 113702 0 0 RequestResponseStage 0 0 0 0 0 MutationStage 0 0 164503 0 0 ... InternalResponseStage 0 0 0 0 0 HintedHandoff 0 0 0 0 0 Message type Dropped RANGE_SLICE 0 READ_REPAIR 0 ... REQUEST_RESPONSE 0 COUNTER_MUTATION 0
Nodetool tpstats
#CassandraSummit 2014
nodetool tpstats org.apache.cassandra.metrics:type=ThreadPools,path={internal|request|transport},scope={*},name= {ActiveTasks|PendingTasks|CompletedTasks|CurrentlyBlockedTasks|TotalBlockedTasks} Pool Name Active Pending Completed Blocked All time blocked
ReadStage 0 0 113702 0 0 RequestResponseStage 0 0 0 0 0 MutationStage 0 0 164503 0 0 ... InternalResponseStage 0 0 0 0 0 HintedHandoff 0 0 0 0 0 Message type Dropped RANGE_SLICE 0 READ_REPAIR 0 ... REQUEST_RESPONSE 0 COUNTER_MUTATION 0
Nodetool tpstats
#CassandraSummit 2014
nodetool tpstats org.apache.cassandra.metrics:type=ThreadPools,path={internal|request|transport},scope={*},name= {ActiveTasks|PendingTasks|CompletedTasks|CurrentlyBlockedTasks|TotalBlockedTasks} Pool Name Active Pending Completed Blocked All time blocked
ReadStage 0 0 113702 0 0 RequestResponseStage 0 0 0 0 0 MutationStage 0 0 164503 0 0 ... InternalResponseStage 0 0 0 0 0 HintedHandoff 0 0 0 0 0 Message type Dropped RANGE_SLICE 0 READ_REPAIR 0 ... REQUEST_RESPONSE 0 COUNTER_MUTATION 0
Nodetool tpstats
#CassandraSummit 2014
nodetool tpstats org.apache.cassandra.metrics:type=ThreadPools,path={internal|request|transport},scope={*},name= {ActiveTasks|PendingTasks|CompletedTasks|CurrentlyBlockedTasks|TotalBlockedTasks} Pool Name Active Pending Completed Blocked All time blocked
ReadStage 0 0 113702 0 0 RequestResponseStage 0 0 0 0 0 MutationStage 0 0 164503 0 0 ... InternalResponseStage 0 0 0 0 0 HintedHandoff 0 0 0 0 0 Message type Dropped RANGE_SLICE 0 READ_REPAIR 0 ... REQUEST_RESPONSE 0 COUNTER_MUTATION 0
Nodetool tpstats
#CassandraSummit 2014
nodetool tpstats org.apache.cassandra.metrics:type=ThreadPools,path={internal|request|transport},scope={*},name= {ActiveTasks|PendingTasks|CompletedTasks|CurrentlyBlockedTasks|TotalBlockedTasks} Pool Name Active Pending Completed Blocked All time blocked
ReadStage 0 0 113702 0 0 RequestResponseStage 0 0 0 0 0 MutationStage 0 0 164503 0 0 ... InternalResponseStage 0 0 0 0 0 HintedHandoff 0 0 0 0 0 Message type Dropped RANGE_SLICE 0 READ_REPAIR 0 ... REQUEST_RESPONSE 0 COUNTER_MUTATION 0
Nodetool tpstats
#CassandraSummit 2014
nodetool tpstats org.apache.cassandra.metrics:type=ThreadPools,path={internal|request|transport},scope={*},name= {ActiveTasks|PendingTasks|CompletedTasks|CurrentlyBlockedTasks|TotalBlockedTasks} Pool Name Active Pending Completed Blocked All time blocked
ReadStage 0 0 113702 0 0 RequestResponseStage 0 0 0 0 0 MutationStage 0 0 164503 0 0 ... InternalResponseStage 0 0 0 0 0 HintedHandoff 0 0 0 0 0 Message type Dropped RANGE_SLICE 0 READ_REPAIR 0 ... REQUEST_RESPONSE 0 COUNTER_MUTATION 0
nodetool tpstats org.apache.cassandra.metrics:type=ThreadPools,path={internal|request|transport},scope={*},name= {ActiveTasks|PendingTasks|CompletedTasks|CurrentlyBlockedTasks|TotalBlockedTasks} Pool Name Active Pending Completed Blocked All time blocked
ReadStage 0 0 113702 0 0 RequestResponseStage 0 0 0 0 0 MutationStage 0 0 164503 0 0 ... InternalResponseStage 0 0 0 0 0 HintedHandoff 0 0 0 0 0 Message type Dropped RANGE_SLICE 0 READ_REPAIR 0 ... REQUEST_RESPONSE 0 COUNTER_MUTATION 0
Nodetool tpstats
#CassandraSummit 2014
RequestResponse
Threads
nodetool tpstats org.apache.cassandra.metrics:type=ThreadPools,path={internal|request|transport},scope={*},name= {ActiveTasks|PendingTasks|CompletedTasks|CurrentlyBlockedTasks|TotalBlockedTasks} Pool Name Active Pending Completed Blocked All time blocked
ReadStage 0 0 113702 0 0 RequestResponseStage 0 0 0 0 0 MutationStage 0 0 164503 0 0 ... InternalResponseStage 0 0 0 0 0 HintedHandoff 0 0 0 0 0 Message type Dropped RANGE_SLICE 0 READ_REPAIR 0 ... REQUEST_RESPONSE 1 COUNTER_MUTATION 0
Nodetool tpstats
#CassandraSummit 2014
RequestResponse
Threads
Nodetool tpstats
#CassandraSummit 2014
nodetool tpstats org.apache.cassandra.metrics:type=ThreadPools,path={internal|request|transport},scope={*},name= {ActiveTasks|PendingTasks|CompletedTasks|CurrentlyBlockedTasks|TotalBlockedTasks}
More at: http://www.evidencebasedit.com/guide-to-cassandra-thread-pools
Nodetool cfhistograms
#CassandraSummit 2014
nodetool cfhistograms {keyspace} {table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
SSTables per Read 1 sstables: 98554 2 sstables: 4534 Write Latency (microseconds) No Data Read Latency (microseconds) 10 us: 2 12 us: 17 14 us: 96 17 us: 208 20 us: 677 24 us: 3081 29 us: 4552 35 us: 3559
Read Write Path mile high overview
#CassandraSummit 2014
Memtable SSTable
Writes Reads
Read Write Path mile high overview
#CassandraSummit 2014
Memtable SSTable
Writes Reads
Read Write Path mile high overview
#CassandraSummit 2014
Memtable SSTable
Writes Reads
Read Write Path mile high overview
#CassandraSummit 2014
Memtable SSTable
Writes Reads
Read Write Path mile high overview
#CassandraSummit 2014
Memtable SSTable
Writes Reads
Nodetool cfhistograms
#CassandraSummit 2014
nodetool cfhistograms {keyspace} {table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
SSTables per Read 1 sstables: 98554 2 sstables: 4534 Write Latency (microseconds) No Data Read Latency (microseconds) 10 us: 2 12 us: 17 14 us: 96 17 us: 208 20 us: 677 24 us: 3081 29 us: 4552 35 us: 3559
Nodetool cfhistograms 1.1
#CassandraSummit 2014
Offset SSTables Write Latency Read Latency Row Size Column Count 1 3579 0 0 0 0 2 0 0 0 0 0 . . . 35 0 0 0 0 0 42 0 0 27 0 0 50 0 0 187 0 0 60 0 10 460 0 0 72 0 200 689 0 0 86 0 663 552 0 0 103 0 796 367 0 0 124 0 297 736 0 0 149 0 265 243 0 0 179 0 460 263 0 0 . . . 25109160 0 0 0 0 0
nodetool cfhistograms {keyspace} {table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Nodetool cfhistograms
#CassandraSummit 2014
https://gist.github.com/clohfink/6068003
Nodetool cfhistograms 2.1
#CassandraSummit 2014
nodetool cfhistograms {keyspace} {table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace/Table histograms Percentile SSTables Write Latency Read Latency Partition Size Cell Count (micros) (micros) (bytes) 50% 1.00 10.00 524.00 310 5 75% 1.00 11.75 888.00 310 5 95% 1.00 15.00 4843.75 310 5 98% 1.00 17.00 9658.90 310 5 99% 1.00 19.00 12306.47 310 5 Min 0.00 0.00 68.00 30 0 Max 2.00 1219386.00 45383.00 310 5
Nodetool cfstats
#CassandraSummit 2014
nodetool cfstats {-i} {keyspace}.{table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace: Keyspace1 Read Count: 11207 Read Latency: 0.047931114482020164 ms. Write Count: 17598 Write Latency: 0.053502954881236506 ms. Pending Tasks: 0 Table: Standard1 SSTable count: 3 Space used (live), bytes: 9088955 Space used (total), bytes: 9088955 Space used by snapshots (total), bytes: 0 SSTable Compression Ratio: 0.3672150946 Memtable cell count: 0 Memtable data size, bytes: 0 Memtable switch count: 3
Local read count: 11207 Local read latency: 0.048 ms Local write count: 17598 Local write latency: 0.054 ms Pending tasks: 0 Bloom filter false positives: 0 Bloom filter false ratio: 0.00000 Bloom filter space used, bytes: 11688 Compacted partition minimum bytes: 1110 Compacted partition maximum bytes: 126934 Compacted partition mean bytes: 2730 Average live cells per slice: 0.0 Average tombstones per slice: 0.0
Nodetool cfstats
#CassandraSummit 2014
nodetool cfstats {-i} {keyspace}.{table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace: Keyspace1 Read Count: 11207 Read Latency: 0.047931114482020164 ms. Write Count: 17598 Write Latency: 0.053502954881236506 ms. Pending Tasks: 0 Table: Standard1 SSTable count: 3 Space used (live), bytes: 9088955 Space used (total), bytes: 9088955 Space used by snapshots (total), bytes: 0 SSTable Compression Ratio: 0.3672150946 Memtable cell count: 0 Memtable data size, bytes: 0 Memtable switch count: 3
Local read count: 11207 Local read latency: 0.048 ms Local write count: 17598 Local write latency: 0.054 ms Pending tasks: 0 Bloom filter false positives: 0 Bloom filter false ratio: 0.00000 Bloom filter space used, bytes: 11688 Compacted partition minimum bytes: 1110 Compacted partition maximum bytes: 126934 Compacted partition mean bytes: 2730 Average live cells per slice: 0.0 Average tombstones per slice: 0.0
Nodetool cfstats
#CassandraSummit 2014
nodetool cfstats {-i} {keyspace}.{table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace: Keyspace1 Read Count: 11207 Read Latency: 0.047931114482020164 ms. Write Count: 17598 Write Latency: 0.053502954881236506 ms. Pending Tasks: 0 Table: Standard1 SSTable count: 3 Space used (live), bytes: 9088955 Space used (total), bytes: 9088955 Space used by snapshots (total), bytes: 0 SSTable Compression Ratio: 0.3672150946 Memtable cell count: 0 Memtable data size, bytes: 0 Memtable switch count: 3
Local read count: 11207 Local read latency: 0.048 ms Local write count: 17598 Local write latency: 0.054 ms Pending tasks: 0 Bloom filter false positives: 0 Bloom filter false ratio: 0.00000 Bloom filter space used, bytes: 11688 Compacted partition minimum bytes: 1110 Compacted partition maximum bytes: 126934 Compacted partition mean bytes: 2730 Average live cells per slice: 0.0 Average tombstones per slice: 0.0
Nodetool cfstats
#CassandraSummit 2014
nodetool cfstats {-i} {keyspace}.{table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace: Keyspace1 Read Count: 11207 Read Latency: 0.047931114482020164 ms. Write Count: 17598 Write Latency: 0.053502954881236506 ms. Pending Tasks: 0 Table: Standard1 SSTable count: 3 Space used (live), bytes: 9088955 Space used (total), bytes: 9088955 Space used by snapshots (total), bytes: 0 SSTable Compression Ratio: 0.3672150946 Memtable cell count: 0 Memtable data size, bytes: 0 Memtable switch count: 3
Local read count: 11207 Local read latency: 0.048 ms Local write count: 17598 Local write latency: 0.054 ms Pending tasks: 0 Bloom filter false positives: 0 Bloom filter false ratio: 0.00000 Bloom filter space used, bytes: 11688 Compacted partition minimum bytes: 1110 Compacted partition maximum bytes: 126934 Compacted partition mean bytes: 2730 Average live cells per slice: 0.0 Average tombstones per slice: 0.0
Nodetool cfstats
#CassandraSummit 2014
nodetool cfstats {-i} {keyspace}.{table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace: Keyspace1 Read Count: 11207 Read Latency: 0.047931114482020164 ms. Write Count: 17598 Write Latency: 0.053502954881236506 ms. Pending Tasks: 0 Table: Standard1 SSTable count: 3 SSTables in each level: [14/4, 1, 0, …, 0] Space used (live), bytes: 9088955 Space used (total), bytes: 9088955 Space used by snapshots (total), bytes: 0 SSTable Compression Ratio: 0.3672150946 Memtable cell count: 0 Memtable data size, bytes: 0 Memtable switch count: 3
Local read count: 11207 Local read latency: 0.048 ms Local write count: 17598 Local write latency: 0.054 ms Pending tasks: 0 Bloom filter false positives: 0 Bloom filter false ratio: 0.00000 Bloom filter space used, bytes: 11688 Compacted partition minimum bytes: 1110 Compacted partition maximum bytes: 126934 Compacted partition mean bytes: 2730 Average live cells per slice: 0.0 Average tombstones per slice: 0.0
Nodetool cfstats
#CassandraSummit 2014
nodetool cfstats {-i} {keyspace}.{table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace: Keyspace1 Read Count: 11207 Read Latency: 0.047931114482020164 ms. Write Count: 17598 Write Latency: 0.053502954881236506 ms. Pending Tasks: 0 Table: Standard1 SSTable count: 3 Space used (live), bytes: 9088955 Space used (total), bytes: 9088955 Space used by snapshots (total), bytes: 0 SSTable Compression Ratio: 0.3672150946 Memtable cell count: 0 Memtable data size, bytes: 0 Memtable switch count: 3
Local read count: 11207 Local read latency: 0.048 ms Local write count: 17598 Local write latency: 0.054 ms Pending tasks: 0 Bloom filter false positives: 0 Bloom filter false ratio: 0.00000 Bloom filter space used, bytes: 11688 Compacted partition minimum bytes: 1110 Compacted partition maximum bytes: 126934 Compacted partition mean bytes: 2730 Average live cells per slice: 0.0 Average tombstones per slice: 0.0
Nodetool cfstats
#CassandraSummit 2014
nodetool cfstats {-i} {keyspace}.{table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace: Keyspace1 Read Count: 11207 Read Latency: 0.047931114482020164 ms. Write Count: 17598 Write Latency: 0.053502954881236506 ms. Pending Tasks: 0 Table: Standard1 SSTable count: 3 Space used (live), bytes: 9088955 Space used (total), bytes: 9088955 Space used by snapshots (total), bytes: 0 SSTable Compression Ratio: 0.3672150946 Memtable cell count: 0 Memtable data size, bytes: 0 Memtable switch count: 3
Local read count: 11207 Local read latency: 0.048 ms Local write count: 17598 Local write latency: 0.054 ms Pending tasks: 0 Bloom filter false positives: 0 Bloom filter false ratio: 0.00000 Bloom filter space used, bytes: 11688 Compacted partition minimum bytes: 1110 Compacted partition maximum bytes: 126934 Compacted partition mean bytes: 2730 Average live cells per slice: 0.0 Average tombstones per slice: 0.0
Nodetool cfstats
#CassandraSummit 2014
nodetool cfstats {-i} {keyspace}.{table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace: Keyspace1 Read Count: 11207 Read Latency: 0.047931114482020164 ms. Write Count: 17598 Write Latency: 0.053502954881236506 ms. Pending Tasks: 0 Table: Standard1 SSTable count: 3 Space used (live), bytes: 9088955 Space used (total), bytes: 9088955 Space used by snapshots (total), bytes: 0 SSTable Compression Ratio: 0.3672150946 Memtable cell count: 0 Memtable data size, bytes: 0 Memtable switch count: 3
Local read count: 11207 Local read latency: 0.048 ms Local write count: 17598 Local write latency: 0.054 ms Pending tasks: 0 Bloom filter false positives: 0 Bloom filter false ratio: 0.00000 Bloom filter space used, bytes: 11688 Compacted partition minimum bytes: 1110 Compacted partition maximum bytes: 126934 Compacted partition mean bytes: 2730 Average live cells per slice: 0.0 Average tombstones per slice: 0.0
Nodetool cfstats
#CassandraSummit 2014
nodetool cfstats {-i} {keyspace}.{table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace: Keyspace1 Read Count: 11207 Read Latency: 0.047931114482020164 ms. Write Count: 17598 Write Latency: 0.053502954881236506 ms. Pending Tasks: 0 Table: Standard1 SSTable count: 3 Space used (live), bytes: 9088955 Space used (total), bytes: 9088955 Space used by snapshots (total), bytes: 0 SSTable Compression Ratio: 0.3672150946 Memtable cell count: 0 Memtable data size, bytes: 0 Memtable switch count: 3
Local read count: 11207 Local read latency: 0.048 ms Local write count: 17598 Local write latency: 0.054 ms Pending tasks: 0 Bloom filter false positives: 0 Bloom filter false ratio: 0.00000 Bloom filter space used, bytes: 11688 Compacted partition minimum bytes: 1110 Compacted partition maximum bytes: 126934 Compacted partition mean bytes: 2730 Average live cells per slice: 0.0 Average tombstones per slice: 0.0
Nodetool cfstats
#CassandraSummit 2014
nodetool cfstats {-i} {keyspace}.{table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace: Keyspace1 Read Count: 11207 Read Latency: 0.047931114482020164 ms. Write Count: 17598 Write Latency: 0.053502954881236506 ms. Pending Tasks: 0 Table: Standard1 SSTable count: 3 Space used (live), bytes: 9088955 Space used (total), bytes: 9088955 Space used by snapshots (total), bytes: 0 SSTable Compression Ratio: 0.3672150946 Memtable cell count: 0 Memtable data size, bytes: 0 Memtable switch count: 3
Local read count: 11207 Local read latency: 0.048 ms Local write count: 17598 Local write latency: 0.054 ms Pending tasks: 0 Bloom filter false positives: 0 Bloom filter false ratio: 0.00000 Bloom filter space used, bytes: 11688 Compacted partition minimum bytes: 1110 Compacted partition maximum bytes: 126934 Compacted partition mean bytes: 2730 Average live cells per slice: 0.0 Average tombstones per slice: 0.0
Nodetool cfstats
#CassandraSummit 2014
nodetool cfstats {-i} {keyspace}.{table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace: Keyspace1 Read Count: 11207 Read Latency: 0.047931114482020164 ms. Write Count: 17598 Write Latency: 0.053502954881236506 ms. Pending Tasks: 0 Table: Standard1 SSTable count: 3 Space used (live), bytes: 9088955 Space used (total), bytes: 9088955 Space used by snapshots (total), bytes: 0 SSTable Compression Ratio: 0.3672150946 Memtable cell count: 0 Memtable data size, bytes: 0 Memtable switch count: 3
Local read count: 11207 Local read latency: 0.048 ms Local write count: 17598 Local write latency: 0.054 ms Pending tasks: 0 Bloom filter false positives: 0 Bloom filter false ratio: 0.00000 Bloom filter space used, bytes: 11688 Compacted partition minimum bytes: 1110 Compacted partition maximum bytes: 126934 Compacted partition mean bytes: 2730 Average live cells per slice: 0.0 Average tombstones per slice: 0.0
Nodetool cfstats
#CassandraSummit 2014
nodetool cfstats {-i} {keyspace}.{table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace: Keyspace1 Read Count: 11207 Read Latency: 0.047931114482020164 ms. Write Count: 17598 Write Latency: 0.053502954881236506 ms. Pending Tasks: 0 Table: Standard1 SSTable count: 3 Space used (live), bytes: 9088955 Space used (total), bytes: 9088955 Space used by snapshots (total), bytes: 0 SSTable Compression Ratio: 0.3672150946 Memtable cell count: 0 Memtable data size, bytes: 0 Memtable switch count: 3
Local read count: 11207 Local read latency: 0.048 ms Local write count: 17598 Local write latency: 0.054 ms Pending tasks: 0 Bloom filter false positives: 0 Bloom filter false ratio: 0.00000 Bloom filter space used, bytes: 11688 Compacted partition minimum bytes: 1110 Compacted partition maximum bytes: 126934 Compacted partition mean bytes: 2730 Average live cells per slice: 0.0 Average tombstones per slice: 0.0
Nodetool cfstats
#CassandraSummit 2014
nodetool cfstats {-i} {keyspace}.{table} org.apache.cassandra.metrics:type=ColumnFamily,keyspace={keyspace},scope={table}
Keyspace: Keyspace1 Read Count: 11207 Read Latency: 0.047931114482020164 ms. Write Count: 17598 Write Latency: 0.053502954881236506 ms. Pending Tasks: 0 Table: Standard1 SSTable count: 3 Space used (live), bytes: 9088955 Space used (total), bytes: 9088955 Space used by snapshots (total), bytes: 0 SSTable Compression Ratio: 0.3672150946 Memtable cell count: 0 Memtable data size, bytes: 0 Memtable switch count: 3
Local read count: 11207 Local read latency: 0.048 ms Local write count: 17598 Local write latency: 0.054 ms Pending tasks: 0 Bloom filter false positives: 0 Bloom filter false ratio: 0.00000 Bloom filter space used, bytes: 11688 Compacted partition minimum bytes: 1110 Compacted partition maximum bytes: 126934 Compacted partition mean bytes: 2730 Average live cells per slice: 0.0 Average tombstones per slice: 0.0
Nodetool proxyhistograms
#CassandraSummit 2014
nodetool proxyhistograms org.apache.cassandra.metrics:type=ClientRequest,scope={Read|Write|RangeSlice},name=Latency
$ nodetool proxyhistograms proxy histograms Read Latency (microseconds) 61214 us: 1 Write Latency (microseconds) 103 us: 22 124 us: 142 149 us: 297 179 us: 1190 215 us: 1823 258 us: 2091
...
Nodetool compactionstats
#CassandraSummit 2014
nodetool compactionstats org.apache.cassandra.metrics:type=Compaction
pending tasks: 1
compaction type keyspace table completed total unit Progress
Compaction Keyspace1 Standard1 6076415 29605054 bytes 20.06%
Active compaction remaining time : 0h00m03s
Nodetool compactionstats
#CassandraSummit 2014
nodetool compactionstats org.apache.cassandra.metrics:type=Compaction
pending tasks: 1
compaction type keyspace table completed total unit Progress
Compaction Keyspace1 Standard1 6076415 29605054 bytes 20.06%
Active compaction remaining time : 0h00m03s
Nodetool compactionstats
#CassandraSummit 2014
nodetool compactionstats org.apache.cassandra.metrics:type=Compaction
pending tasks: 1
compaction type keyspace table completed total unit Progress
Compaction Keyspace1 Standard1 6076415 29605054 bytes 20.06%
Active compaction remaining time : 0h00m03s
Nodetool compactionstats
#CassandraSummit 2014
nodetool compactionstats org.apache.cassandra.metrics:type=Compaction
pending tasks: 1
compaction type keyspace table completed total unit Progress
Compaction Keyspace1 Standard1 6076415 29605054 bytes 20.06%
Active compaction remaining time : 0h00m03s
Nodetool
#CassandraSummit 2014
Much more!! http://www.datastax.com/documentation/cassandra/2.0/cassandra/tools/toolsNodetool_r.html
OpsCenter
#CassandraSummit 2014
● Provides visibility to key metrics ● Alarming ● Basic orchestration and config management ● Constantly improving ● Free* ● Almost zero barrier to get setup ● Very few reasons not to run it
OpsCenter
#CassandraSummit 2014
● Homogeneous tooling with rest of stack o Integrate metrics in with what app is using o orchestration and config management
● (paid version) “Good enough” o a mature environment should have more
Reporting Interface
#CassandraSummit 2014
Default Addons Community
JMX Ganglia Cassandra StatsD NewRelic Splunk
Console Graphite Cloudwatch Kafka Riemann TempDB
Csv Munin Riak InfluxDB Sematext
Slf4j MongoDB OpenTSDB Librato … MORE
Reporting Interface
#CassandraSummit 2014
● Configurable with yaml o console, csv, ganglia, graphite
● Create reporter with premain agent o compiling new jar with manifest o add to classpath o add javaagent in cassandra-env.sh
Garbage Collection
#CassandraSummit 2014
● Death, Taxes, and a stop the world GC ● Common issue to all JVM based applications
Garbage Collection
#CassandraSummit 2014
Enable gc logging ● Virtually no overhead ● Can be very helpful in diagnosing
performance issues
Garbage Collection
#CassandraSummit 2014
JVM_OPTS="$JVM_OPTS -XX:+PrintGCDetails" JVM_OPTS="$JVM_OPTS -XX:+PrintGCDateStamps" JVM_OPTS="$JVM_OPTS -XX:+PrintHeapAtGC" JVM_OPTS="$JVM_OPTS -XX:+PrintTenuringDistribution" JVM_OPTS="$JVM_OPTS -XX:+PrintGCApplicationStoppedTime" JVM_OPTS="$JVM_OPTS -XX:+PrintPromotionFailure" JVM_OPTS="$JVM_OPTS -XX:PrintFLSStatistics=1" JVM_OPTS="$JVM_OPTS -Xloggc:/var/log/cassandra/gc-`date +%s`.log" JVM_OPTS="$JVM_OPTS -Xloggc:/var/log/cassandra/gc.log" JVM_OPTS="$JVM_OPTS -XX:+UseGCLogFileRotation" JVM_OPTS="$JVM_OPTS -XX:NumberOfGCLogFiles=10" JVM_OPTS="$JVM_OPTS -XX:GCLogFileSize=10M"
Garbage Collection
#CassandraSummit 2014
JVM_OPTS="$JVM_OPTS -XX:+PrintGCDetails" JVM_OPTS="$JVM_OPTS -XX:+PrintGCDateStamps" JVM_OPTS="$JVM_OPTS -XX:+PrintHeapAtGC" JVM_OPTS="$JVM_OPTS -XX:+PrintTenuringDistribution" JVM_OPTS="$JVM_OPTS -XX:+PrintGCApplicationStoppedTime" JVM_OPTS="$JVM_OPTS -XX:+PrintPromotionFailure" JVM_OPTS="$JVM_OPTS -XX:PrintFLSStatistics=1" JVM_OPTS="$JVM_OPTS -Xloggc:/var/log/cassandra/gc-`date +%s`.log" JVM_OPTS="$JVM_OPTS -Xloggc:/var/log/cassandra/gc.log" JVM_OPTS="$JVM_OPTS -XX:+UseGCLogFileRotation" JVM_OPTS="$JVM_OPTS -XX:NumberOfGCLogFiles=10" JVM_OPTS="$JVM_OPTS -XX:GCLogFileSize=10M"
Garbage Collection
#CassandraSummit 2014
Could be its own talk Honorable mentions: ● https://github.com/chewiebug/GCViewer ● http://jworks.idv.tw/GcWeb/ ● Python, R, Octave
Logging
#CassandraSummit 2014
/var/log/cassandra/system.log o provides a rolling log o log4j
/var/log/cassandra/output.log o captured standard error and standard out o truncated on restart
System Logs o syslog, dmesg, etc
OS Metrics
#CassandraSummit 2014
Shout-out: http://www.brendangregg.com/linuxperf.html
JVM
#CassandraSummit 2014
● Heap o GC logs o JMX
● Threads o jvmtop o Jstack (+htop) o kill -3 o JMX
And Everything
#CassandraSummit 2014
Questions
#CassandraSummit 2014
?
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