# 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 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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