I am using mongodb 3.4 (with wiredtiger), with several replica sets, and it’s 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 SO (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 mongo (i.e. this disk will be used exclusively for mongo).

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? (@stennie, save me)

Thanks 🙂