Everything You Never Knew You Wanted to Ask about Time Series Databases

This talk covers the Graphite ecosystem. It is intended to serve as an introduction to core concepts. I also highlight some gotchas I see people run into when they start using time series databases.

Transcript

1. Everything you never knew you wanted to ask about Time Series Data Presented by: Brad Lhotsky
2. You gotta know where I’ve been to know where we’re going.
4. http://oss.oetiker.ch/rrdtool/
5. Reverse Polish Notation!!!
6. Where are we now?
7. Open Source Solutions Graphite OpenTSDB InfluxDB Hosted Solutions Circonus Librato Datadog New Relic
8. What do you use?
10. • Pros • Easy to send metrics • Support for “Metrics 2.0” • SQL-ish interface to the data •Cons • Read scalability is lacking • Still quite young, good things to come here! InfluxDB
11. • Pros • Easy to send metrics • Support for “Metrics 2.0” • Hbase backend • No “roll up” all points stored for eternity! •Cons • Read scalability is lacking • Hbase backend? OpenTSDB
12. YMMV, and that’s O.K.
13. Why do you use Graphite?
14. It’s Open Source.
15. It’s scalable.
16. It’s easy.
17. It’s composable.
18. It’s FUN!
19. What is Time Series Data?
20. Measurements at fixed regular intervals, impossible to have two values for the same metric at the same point in time. Graphite’s rules are that the last value for an interval wins. Time Series Data
21. Graphite does not care, it just stores a value at a point in time. It’s up to you to store what you want and understand how to retrieve it. Gauge v. Counter
22. Gauges usually fit within a fixed range, but only represent state at the time of reading, meaning you can miss spikes. Counters allow more complete history, but can overflow. Use nonNegativeDerivative() to view the changes between points. Gauge v. Counter
23. How does Graphite work?
24. • Dot separated namespaces: • sys.datacenter.zone.host.class.metric • Created automatically the first time it’s updated • All storage pre-allocated • Multiple storage engines • Whisper (Flat Files) • Ceres • Cyanite (based on Cassandra) Metrics
25. • Ask for a metric • sys.datacenter.zone.host.class.metric • Ask for all the metrics • sys.datacenter.zone.*.class.metric • Ask for a combination, mutation, or selection • sumSeries(sys.datacenter.zone.*.class .metric) • Returns PNG, SVG, JSON, CSV, … Queries / API
26. • carbon • Route and store metrics • whisper • Storage file format and utilities • graphite-web • User-facing interface to Graphite Components
27. How does Graphite scale?
28. • Cluster using relays • Use SSD’s for fast writes • Use redundancy because SSD’s fail • Read Jason Dixon’s book With Knowledge, Well.
29. • https://github.com/grobian/carbon-c-relay • Pass and route metrics to storage • https://github.com/dgryski/carbonzipper • Map/Reduce metric queries • https://github.com/dgryski/carbonapi • Intelligent caching layer for JSON/CSV/Raw outputs With Help, WebScale 2.0!!
30. Would you deploy Graphite today?
31. Yes.
32. How does Graphite store data?
33. Every metric is a flat file on disk that’s pre- allocated at creation time to a fixed size. Size is based on the the defined retention periods, which we’ll discuss shortly. Whisper Files
34. The dots in the metric names are directory separators on the file system. Whisper Files
35. Time series databases allow for prolonged storage. It’s common for metrics to remain for two or more years. To cut costs, aggregations are performed as the data ages. Data Compression
36. What do I need to know about roll up?
37. Backend configuration for allocating on disk storage for metrics. Can only be set at metric creation. Define retentions. Storage: Schema [mysql] pattern = ^mysql\. retentions = 10s:2d,60s:14d,30m:2y [default] pattern = .* retentions = 60s:14d,30m:2y
38. Configuration for handling how metrics traverse the retention boundaries. Storage: AGGREGATIONS [default] pattern = .* xFilesFactor = 0.5 aggregationMethod = average
39. Float between 0 and 1 representing the percentage of non-null points required to roll up to a non-null value. xFilesFactor [default] pattern = .* xFilesFactor = 0.5 aggregationMethod = average
40. Functions available to turn multiple values into a single value for retention roll ups. Aggregators ‣ average - Average all values ‣ min - minimum of set ‣ max - maximum of set ‣ sum - sum of set ‣ last - take the last value
41. Storage: AGGREGATIONS [alerts] pattern = ^alerts\. xFilesFactor = 0 aggregationMethod = sum
42. We lose resolution as data rolls up. Rolling Data 1 Minute 5 Minutes 25 Minutes
43. How do I get data in?
44. Getting your data into Graphite is as simple as sending the metric string to the relevant carbon host and port! Sending Data echo “metric.name.as.dotted.path value epoch” \ nc graphite 2003
45. There are a lot of libraries that encapsulate most to all of this incredibly complicated task for every web-scale programming language.
46. Pretty pictures, please?
48. http://obfuscurity.com/2012/04/Unhelpful-Graphite-Tip-2
49. Autocomplete can’t be disabled, use Esc key to close it. Interface
50. security.logging.indexer.*.total Metrics: Wildcards
51. security.logging.indexer.logproc-[12]01.total Metrics: Character Classes
52. security.logging.indexer.logproc-{202,102}.total Metrics: Word Groups
53. aliasByNode(security.logging.indexer.*.total,3) Metrics: Aliases
54. sumSeries(security.logging.indexer.*.total) Combining Metrics
55. sumSeriesWithWildcards(security.logging.indexer.*.*,3) Combining & Grouping Metrics
56. averageSeries(security.logging.indexer.*.total) Combining Metrics
57. averageSeriesWithWildcards( security.logging.indexer.*.{total,ignore}, 3) Combining & Grouping Metrics
58. averageSeriesWithWildcards( security.logging.indexer.*.*,3) Combining Metrics
59. nPercentile(security.logging.indexer.*.total,95) Combining Metrics
60. percentileOfSeries(security.logging.indexer.*.total,95) Combining Metrics
61. mostDeviant(2,security.logging.indexer.*.total) Selecting Metrics
62. highestCurrent(security.logging.indexer.*.total,2) Selecting Metrics
63. highestAverage(security.logging.indexer.*.total,2) Selecting Metrics
64. general.es.logsearch-208.jvm.gc.collectors.old.collection_ms Transforming Metrics general.es.logsearch-201.indices.indexing.index_ms
65. general.es.logsearch-208.jvm.gc.collectors.old.collection_ms Side Bar: Y-Minimun as 0
66. nonNegativeDerivative( general.es.logsearch-208.jvm.gc.collectors.old.collection_ms) Transforming Metrics nonNegativeDerivative( general.es.logsearch-201.indices.indexing.index_ms)
67. removeAbovePercentile( nonNegativeDerivative( general.es.logsearch-201.indices.indexing.index_ms ), 95) Selecting Data
68. scaleToSeconds( removeAbovePercentile( nonNegativeDerivative( general.es.logsearch-201.indices.indexing.index_ms ), 95), 1) Per Second
69. nonNegativeDerivative( general.es.logsearch-208.jvm.gc.collectors.old.collection_ms) Transforming Metrics
70. offset( nonNegativeDerivative( general.es.logsearch-208.jvm.gc.collectors.old.collection_ms ), -30) Transforming Metrics
71. drawAsInfinite( offset( nonNegativeDerivative( general.es.logsearch-208.jvm.gc.collectors.old.collection_ms ), -30) ) Transforming Metrics
72. alias(sumSeries(security.logging.indexer.*.total),”Today") alias( timeShift( sumSeries(security.logging.indexer.*.total), “7d"), "Last Week") Comparing Metrics
73. color(constantLine(0),"red") diffSeries( sumSeries(security.logging.indexer.*.total), timeShift(sumSeries(security.logging.indexer.*.total),”7d") ) Comparing Metrics
74. alias(alpha(color(areaBetween( holtWintersConfidenceBands( maxSeries(general.es.logsearch-20*.jvm.mem.heap_used_bytes) ) ),“gray"),0.1),"Hot Winter Confidence Bands”) color(alias( maxSeries(general.es.logsearch-20*.jvm.mem.heap_used_bytes), "Max Heap Size"),"red") Advanced Tricks
75. # Same as last slide & set Y-Minimum to 0 color(alias( secondYAxis( maxSeries(general.es.logsearch-20*.indices.docs.count) ), "Max Docs per Node"),"green") Advanced Tricks
76. drawAsInfinite( removeBelowValue( offset( nonNegativeDerivative( general.es.logsearch-*.jvm.gc.collectors.old.collection_ms ), -250), 0) ) Advanced Tricks
77. Do you even Dashboard?
78. Grafana http://grafana.org/
79. GraphExplorer https://vimeo.github.io/graph-explorer/
80. Cubism https://square.github.io/cubism/
81. Rubics Cubism https://github.com/reyjrar/rubics-cubism
82. Thank you! brad.lhotsky@gmail.com https://twitter.com/reyjrar https://github.com/reyjrar https://speakerdeck.com/reyjrar