I use 2 approaches to connect to MongoDB server on Droplet from my computer. ( via SSH tunneling and vie URL). I check and see CPU ( of the Droplet ) utilizes only 6%, Top Disk IO is 0.3M/s. I achieved very low writing speed to Droplet, 12000 documents in 936 second, around 12 documents per second.
My document is very short: just one term ( 1 word or 2 words ) and one explanation ( usually 1 short sentence).
Where should be the problem ?