[collectd] write_MongoDB Error

[Zhou, Yuantai]

Hi All,
We use write_mongodb plugin on collectd servers to send data to a central mongo db. Started yesterday, we see the write_mongodb error in the syslog: 

	write_mongodb plugin: error inserting record: 7
	write_mongodb plugin: Resource temporarily unavailable
	write_mongodb plugin: error inserting record: 7
	write_mongodb plugin: Resource temporarily unavailable

The mongo db seems to be running fine. Some collectd data is getting into the mongo but with a pretty significant delay when checked with timestamp. 

Any suggestions on what might cause this error and where we could start troubleshoot?

We use collectd version 5.1.0-3Ubuntu1 on collectd server.

Thanks for your help.
Yuantai