Bulk insert (of 1000 documents) to mongodb server is 1 IOPS in GCP, or it's 1000 iops?

Question

I read GCP docs about performance, and I read about mongo bulk operations, and I'm wondering if bulk operation count as 1 operation (so I can do 30 like that per second per GB for example) or it's equal to the number of operations in the bulk. thank you!

Answer 1

MongoDB bulk operations reduce network and processing overhead but have little effect on disk IOPS.

Disk IOPS are always proportional to the number of documents inserted/updated/deleted, also in bulk mode.

But it's not 1-to-1; in addition to # of documents, disk IOPS are dependent on the indices, journal, checkpoints, shards and cache size.

A very rough estimate would be (2 + #_of_indexes) * #_of_documents_updated / seconds.

Source: Sizing MongoDB Clusters