Percona Server for MongoDB (PSMDB) has provided a hot backup of its underlying data db directory files using WiredTiger library methods since v3.4. When you use the { createBackup: & } command it will copy them to whichever other filesystem directory or object store bucket location you specify. createBackup partially freezes the WiredTiger *.wt Btree [&]

https://www.percona.com/blog/2021/06/07/experimental-feature-backupcursorextend-in-percona-server-for-mongodb/