# 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:

```yaml
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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