I am using MongoDB 3.4 (with WiredTiger) with several replica sets and it has been great so far.
I want to back up my data using snapshots as per the MongoDB recommendation for production backups.
I am also using XFS, as per the MongoDB warning in logs and my question "Is XFS still the best choice for mongodb?".
I moved my disk to LVM (using rsync to transfer all data to the new volume) and I allocated 100% of the VG storage to MongoDB (i.e. this disk will be used exclusively for MongoDB).
As a result I cannot take snapshots because there is no space in the VG, and XFS cannot be shrunk. Furthermore, if any zealous sysadmin runs resize on that disk, I will never be able to take snapshots again.
Is there a good solution to this problem?