I understand Odoo filestore is required for each database we have, if we are saving additional data (attachments, images and so on) outside the database itself (in the filesystem).
If we need to manually move a database to a new server (with pg_dump for instance), we also need to move the filestore.
What about the sessions? Do we need to keep the sessions folder also? Is it safe to completely remove files inside the "sessions" folder?
When you backup Odoo DB with filestore from Odoo it's only create zip file with sql dump file and filestore folder. So you don't need to move the sessions folder content to the new server.