Snapshot backup of Prometheus TSDB


We have setup of single Prometheus Server and have installed exporters (node and postgres) to pull Postgres and OS metrics.

Now we trying to take backup of TSDB as mitigation plan.

Below command is used to take backup

curl -XPOST -u admin http://< server hostnme>:9090/api/v1/admin/tsdb/snapshot

when we are running the aforementioned command multiple times it is creating new directory in snapshots directory but each directory of snapshot is of different size.

Will be great help if i get the information if each snapshot is taking complete backup of TSDB if not then what is the best option to take complete backup of TSDB .

Secondly , is there any way to run backup from Prometheus server itself