mongodb

mongodb

Module monitor mongodb performance and health metrics

Requirements:

• python-pymongo package v2.4+.

You need to install it manually.

Number of charts depends on mongodb version, storage engine and other features (replication):

1. Read requests:

• query
• getmore (operation the cursor executes to get additional data from query)

2. Write requests:

• insert
• delete
• update

3. Active clients:

• readers (number of clients with read operations in progress or queued)
• writers (number of clients with write operations in progress or queued)

4. Journal transactions:

• commits (count of transactions that have been written to the journal)

5. Data written to the journal:

• volume (volume of data)

6. Background flush (MMAPv1):

• average ms (average time taken by flushes to execute)
• last ms (time taken by the last flush)

8. Read tickets (WiredTiger):

• in use (number of read tickets in use)
• available (number of available read tickets remaining)

9. Write tickets (WiredTiger):

• in use (number of write tickets in use)
• available (number of available write tickets remaining)

10. Cursors:

• opened (number of cursors currently opened by MongoDB for clients)
• timedOut (number of cursors that have timed)
• noTimeout (number of open cursors with timeout disabled)

11. Connections:

• connected (number of clients currently connected to the database server)
• unused (number of unused connections available for new clients)

12. Memory usage metrics:

• virtual
• resident (amount of memory used by the database process)
• mapped
• non mapped

13. Page faults:

• page faults (number of times MongoDB had to request from disk)

14. Cache metrics (WiredTiger):

• percentage of bytes currently in the cache (amount of space taken by cached data)
• percantage of tracked dirty bytes in the cache (amount of space taken by dirty data)

15. Pages evicted from cache (WiredTiger):

• modified
• unmodified

16. Queued requests:

• readers (number of read request currently queued)
• writers (number of write request currently queued)

17. Errors:

• msg (number of message assertions raised)
• warning (number of warning assertions raised)
• regular (number of regular assertions raised)
• user (number of assertions corresponding to errors generated by users)

18. Storage metrics (one chart for every database)

• dataSize (size of all documents + padding in the database)
• indexSize (size of all indexes in the database)
• storageSize (size of all extents in the database)

19. Documents in the database (one chart for all databases)

• documents (number of objects in the database among all the collections)

20. tcmalloc metrics

• central cache free
• current total thread cache
• pageheap free
• pageheap unmapped
• thread cache free
• transfer cache free
• heap size

21. Commands total/failed rate

• count
• createIndex
• delete
• eval
• findAndModify
• insert

22. Locks metrics (acquireCount metrics - number of times the lock was acquired in the specified mode)

• Global lock
• Database lock
• Collection lock
• Metadata lock
• oplog lock

23. Replica set members state

• state

24. Oplog window

• window (interval of time between the oldest and the latest entries in the oplog)

25. Replication lag

• member (time when last entry from the oplog was applied for every member)

26. Replication set member heartbeat latency

• member (time when last heartbeat was received from replica set member)

prerequisite

Create a read-only user for the netdata in the admin database.

1. Authenticate as the admin user.

use admin
db.auth("admin", "<MONGODB_ADMIN_PASSWORD>")

2. Create a user.

# MongoDB 2.x.
db.addUser("netdata", "<UNIQUE_PASSWORD>", true)

# MongoDB 3.x or higher.
db.createUser({
  "user":"netdata",
  "pwd": "<UNIQUE_PASSWORD>",
  "roles" : [
    {role: 'read', db: 'admin' },
    {role: 'clusterMonitor', db: 'admin'},
    {role: 'read', db: 'local' }
  ]
})

configuration

Sample:

local:
    name : 'local'
    authdb: 'admin'
    host : '127.0.0.1'
    port : 27017
    user : 'netdata'
    pass : 'netdata'

If no configuration is given, module will attempt to connect to mongodb daemon on 127.0.0.1:27017 address

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