The last time I had to call fsfreeze (or xfs_freeze) before creating an LVM snapshot was maybe 17-18 years ago on a system with rather old (even for the time) "stable" versions of everything, where it was not yet integrated.

Since decades, lvm triggers a freeze before snapshot creation and an unfreeze afterwards, if the filesystem supports it.

> fsfreeze is unnecessary for device-mapper devices. The device-mapper (and LVM) automatically freezes a filesystem on the device when a snapshot creation is requested. For more details see the dmsetup(8) man page.

https://man7.org/linux/man-pages/man8/fsfreeze.8.html

It is part of the VFS:

> freeze_fs > > called when VFS is locking a filesystem and forcing it into a consistent state. This method is currently used by the Logical Volume Manager (LVM) and ioctl(FIFREEZE). Optional.

https://docs.kernel.org/filesystems/vfs.html

All relevant filesystems implement it.

> List of these filesystems include (2016-12-18) btrfs, ext2/3/4, f2fs, jfs, nilfs2, reiserfs, and xfs. Previous list may be incomplete, as more filesystems get support.

Using LVM snapshots is absolutely fine for creating consistent and complete copies of sqlite databases. You have to to copy the rollback-journal or WAL, too: they are part the db, it will checkpoint to the db file when you open it or its copy. Every committed transaction before the snapshot is in it. It is complete.

And even if you do use a mode below PRAGMA synchronous=FULL ( https://sqlite.org/pragma.html#pragma_synchronous ) -- FULL is needed to ensure durability as it fsync()s the WAL on every commit -- you are better of than with a system crash: the freeze writes out every dirty page to disk, which is not guaranteed in case of a crash, where in NORMAL mode, you might lose the transactions written to the WAL file, but not to synced to disk yet.