Sharding with MongoDB -- MongoDC 2012

Introduction to sharding with MongoDB.

Transcript

1. Sharding with MongoDB Tyler Brock @TylerBrock
2. Philosophy Concepts Architecture Mechanics
3. Philosophy
4. Philosophy
5. “Ruby is designed to make programmers happy.” Philosophy
6. Philosophy MongoDB is a database for developers.
7. Build Philosophy
8. Build Scale Philosophy
9. How does MongoDB scale? Philosophy
10. > db.runCommand({enablesharding: "<dbname>" }) > db.runCommand({ shardcollection: "<namespace>", key: <shardkeypatternobject> }) Philosophy
11. Concepts
12. datastore app Read/Write Simple Web Application
13. What happens when your working set exceeds memory?
14. What happens if your write load is enormous?
15. datastore app Vertical Scaling
16. app Vertical Scaling datastore
17. app Vertical Scaling datastore app app 68 GB Ram Raid10 EBS
18. datastore app Vertical Scaling app app 512 GB Ram Raid10 SSD
19. Horizontal Scaling
20. app datastore datastore datastore 60gb Horizontal Scaling
21. app datastore datastore datastore 20gb 20gb 20gb Horizontal Scaling
22. Routing Logic app datastore datastore datastore 20gb 20gb 20gb metadata Horizontal Scaling
23. Routing Logic app datastore datastore datastore 20gb 20gb metadata 60gb Horizontal Scaling
24. app Routing Logic Balancer datastore datastore datastore 20gb 20gb metadata 60gb Horizontal Scaling
25. app Routing Logic Balancer datastore datastore datastore metadata 30gb 30gb 30gb Horizontal Scaling
26. Architecture
27. Really is just a mongod (or replica set) Where your data lives mongod Shard
28. Mongod started with --configsvr option Must have 3 (or 1 in development) Data is commited using 2 phase commit config Config Server
29. mongos Acts just like shard router / proxy One or as many as you want Light weight -- can run on App servers Caches meta-data from config servers mongos
30. Routing Logic Balancing metadata datastore datastore datastore
31. metadata datastore mongos datastore datastore
32. metadata datastore mongos datastore datastore app
33. datastore mongos config datastore datastore app
34. datastore mongos config datastore datastore config config app
35. mongos config mongod mongod mongod config config app
36. mongos config mongod mongod mongod mongod mongod mongod mongod mongod mongod RS RS RS config config app
37. mongos config mongod mongod mongod mongod mongod mongod mongod mongod mongod RS RS RS config config app
38. Configuration
39. mongod mongod mongod Bring up mongods or Replica Sets mongod mongod mongod mongod mongod mongod RS RS RS mongod --shardsvr mongod --replSet --shardsvr
40. config mongod mongod mongod mongod mongod mongod mongod mongod mongod RS RS RS Bring up Config Servers config config mongod --configsvr
41. config mongod mongod mongod mongod mongod mongod mongod mongod mongod RS RS RS Bring up Mongos config config mongos mongos --configdb <list of configdb uris>
42. > use admin > db.runCommand({"addShard": <shard uri>}) Connect to Mongos + Add Shards +Enable Sharding > db.runCommand( { enablesharding : "<dbname>" } ); > db.runCommand( { shardcollection : "<namespace>", key : <key> }); +Shard a Collection
43. Mechanics
44. How does MongoDB balance my data?
45. { name: “Joe”, email: “Joe@fake.com”, }, { name: “Bob”, email: “bob@fake.com”, }, { name: “Tyler”, email: “tyler@fake.com”, } Keys test.users
46. > db.runCommand({ }) { name: “Joe”, email: “Joe@fake.com”, }, { name: “Bob”, email: “bob@fake.com”, }, { name: “Tyler”, email: “tyler@fake.com”, } shardcollection: “test.users”, Keys key: { email: 1 } test.users
47. { name: “Joe”, email: “Joe@fake.com”, }, { name: “Bob”, email: “bob@fake.com”, }, { name: “Tyler”, email: “tyler@fake.com”, } shardcollection: “test.users”, Keys key: { email: 1 } test.users
48. { name: “Joe”, email: “Joe@fake.com”, }, { name: “Bob”, email: “bob@fake.com”, }, { name: “Tyler”, email: “tyler@fake.com”, } Keys key: { email: 1 } test.users
49. Chunks -∞ +∞
50. Chunks -∞ +∞ joe@fake.com moe@fake.com tyler@fake.com
51. Chunks -∞ +∞ Split! joe@fake.com moe@fake.com tyler@fake.com
52. Chunks -∞ +∞ Split! This is a chunk This is a chunk joe@fake.com moe@fake.com tyler@fake.com
53. Chunks -∞ +∞ joe@fake.com moe@fake.com tyler@fake.com
54. Chunks -∞ +∞ joe@fake.com moe@fake.com tyler@fake.com
55. Chunks -∞ +∞ Split! joe@fake.com moe@fake.com tyler@fake.com
56. Splitting config config config mongos Shard 1 Shard 2 Shard 3 Shard 4
57. Splitting config config config mongos Shard 1 Shard 2 Shard 3 Shard 4
58. Splitting config config config mongos Shard 1 Shard 2 Shard 3 Shard 4
59. Splitting config config config mongos Shard 1 Shard 2 Shard 3 Shard 4
60. Splitting config config config mongos Shard 1 Shard 2 Shard 3 Shard 4 Split this big chunk into 2 chunks
61. Splitting config config config mongos Shard 1 Shard 2 Shard 3 Shard 4
62. Splitting config config config mongos Shard 1 Shard 2 Shard 3 Shard 4 These chunks have split
63. Balancing config config config mongos Shard 1 Shard 2 Shard 3 Shard 4
64. Balancing config config config mongos Shard 1 Shard 2 Shard 3 Shard 4 Shard1, move a chunk to Shard2
65. Balancing config config config mongos Shard 1 Shard 2 Shard 3 Shard 4
66. Balancing config config config mongos Shard 1 Shard 2 Shard 3 Shard 4 Shard1, move another chunk to Shard3
67. Balancing config config config mongos Shard 1 Shard 2 Shard 3 Shard 4
68. Balancing config config config mongos Shard 1 Shard 2 Shard 3 Shard 4 Shard1, move another chunk to Shard4
69. Balancing config config config mongos Shard 1 Shard 2 Shard 3 Shard 4
70. Balancing config config config mongos Shard 1 Shard 2 Shard 3 Shard 4
71. How does MongoDB route my queries?
72. Routed Request mongos shard shard shard
73. Routed Request 1 mongos shard shard shard 1. Query arrives at Mongos
74. Routed Request 1 2 mongos shard shard shard 1. Query arrives at Mongos 2. Mongos routes query to a single shard
75. Routed Request 1 2 3 mongos shard shard shard 1. Query arrives at Mongos 2. Mongos routes query to a single shard 3. Shard returns results of query
76. Routed Request 1 2 3 4 mongos shard shard shard 1. Query arrives at Mongos 2. Mongos routes query to a single shard 3. Shard returns results of query 4. Results returned to client
77. Scatter Gather Request shard shard shard mongos
78. Scatter Gather Request 1 1. Query arrives at Mongos shard shard shard mongos
79. Scatter Gather Request 1 1. Query arrives at Mongos 2 2 2 shard shard shard mongos 2. Mongos broadcasts query to all shards
80. Scatter Gather Request 1 1. Query arrives at Mongos 2 2 2 3 3 3 shard shard shard mongos 2. Mongos broadcasts query to all shards 3. Each shard returns results for query
81. Scatter Gather Request 1 4 1. Query arrives at Mongos 2 2 2 3 3 3 shard shard shard mongos 2. Mongos broadcasts query to all shards 3. Each shard returns results for query 4. Results combined and returned to client
82. mongos Distributed Merge Sort Req. shard shard shard
83. mongos Distributed Merge Sort Req. 1 shard shard shard 1. Query arrives at Mongos
84. mongos Distributed Merge Sort Req. 1 2 2 2 shard shard shard 1. Query arrives at Mongos 2. Mongos broadcasts query to all shards
85. mongos Distributed Merge Sort Req. 1 2 2 2 shard shard shard 3 3 3 1. Query arrives at Mongos 2. Mongos broadcasts query to all shards 3. Each shard locally sorts results
86. mongos Distributed Merge Sort Req. 1 2 2 2 4 4 4 shard shard shard 3 3 3 1. Query arrives at Mongos 2. Mongos broadcasts query to all shards 3. Each shard locally sorts results 4. Results returned to mongos
87. mongos Distributed Merge Sort Req. 1 5 2 2 2 4 4 4 shard shard shard 3 3 3 1. Query arrives at Mongos 2. Mongos broadcasts query to all shards 3. Each shard locally sorts results 4. Results returned to mongos 5. Mongos merges sorted results
88. mongos Distributed Merge Sort Req. 1 6 5 2 2 2 4 4 4 shard shard shard 3 3 3 1. Query arrives at Mongos 2. Mongos broadcasts query to all shards 3. Each shard locally sorts results 4. Results returned to mongos 5. Mongos merges sorted results 6. Combined results returned to client
89. Queries By Shard Key Routed db.users.find({email: “bob@10gen.com”}) Sorted by shard key Routed in order db.users.find().sort({email:-1}) Find by non shard key Scatter Gather db.users.find({state:”NY”}) Sorted by non shard key Distributed merge sort db.users.find().sort({state:1})
90. Writes Inserts Requires shard key db.users.insert({ name: “Bob”, email: “Bob@fake.com”}) Removes Routed db.users.delete({ email: “bob@fake.com”}) Removes Scattered db.users.delete({name: “Bob”}) Updates Routed db.users.update( {email: “bob@10gen.com”}, {$set: { state: “NY”}}) Updates Scattered db.users.update( {state: “CA”}, {$set:{ state: “NY”}} )
91. How do I choose my shard key?
92. Choose a field that is common to your queries. Rule of Thumb
93. Cardinality Chunks should be able to split.
94. Bad {node: 1} { node: "ny153.example.com", application: "apache", time: "2011-01-02T21:21:56Z", level: "ERROR", msg: "something is broken" } Chunks should be able to split
95. Better {node:1, time:1} Bad {node: 1} { node: "ny153.example.com", application: "apache", time: "2011-01-02T21:21:56Z", level: "ERROR", msg: "something is broken" } Chunks should be able to split
96. Write Scaling Writes should be distributed.
97. { node: "ny153.example.com", application: "apache", time: "2011-01-02T21:21:56Z", level: "ERROR", msg: "something is broken" } Bad { time : 1 } Writes should be distributed
98. { node: "ny153.example.com", application: "apache", time: "2011-01-02T21:21:56Z", level: "ERROR", msg: "something is broken" } Bad { time : 1 } Better {node:1, application:1, time:1} Writes should be distributed
99. Query Isolation & Data Locality Queries should be routed to one shard.
100. Bad {msg: 1, node: 1} { node: "ny153.example.com", application: "apache", time: "2011-01-02T21:21:56Z", level: "ERROR", msg: "something is broken” } Queries should be routed to one shard
101. Better {node: 1, time: 1} Bad {msg: 1, node: 1} { node: "ny153.example.com", application: "apache", time: "2011-01-02T21:21:56Z", level: "ERROR", msg: "something is broken” } Queries should be routed to one shard
102. > db.runCommand({enablesharding: "<dbname>" }) > db.runCommand({ shardcollection: "<namespace>", key: <shardkeypatternobject> })
103. Thanks!
104. Extra Slides
105. Config Servers
106. Config Servers mongod
107. Config Servers mongod mongod mongod
108. mongoDB Scaling - Single Node write read node_a1
109. Read scaling - add Replicas write read node_b1 node_a1
110. Read scaling - add Replicas write read node_c1 node_b1 node_a1
111. Write scaling - Sharding shard1 write read node_c1 node_b1 node_a1
112. Write scaling - add shards write read shard1 node_c1 node_b1 node_a1 shard2 node_c2 node_b2 node_a2
113. Write scaling - add shards write read shard1 node_c1 node_b1 node_a1 shard2 node_c2 node_b2 node_a2 shard3 node_c3 node_b3 node_a3