it’s equivalent to backing up a server after a hard power off.
as long as the filesystem supports some kind of journaling (aka it’s not ancient) and the database is acid compliant, there shouldn’t be any major issues beyond a slow startup.
but keep in mind that you may lose acid compliance by fiddling with the disk flushing configuration, which is a common trick to raise write speed on write choked databases. if that’s the case you may lose some transactions
your database documentation should have this information.
as long as the filesystem supports some kind of journaling (aka it’s not ancient) and the database is acid compliant, there shouldn’t be any major issues beyond a slow startup.
but keep in mind that you may lose acid compliance by fiddling with the disk flushing configuration, which is a common trick to raise write speed on write choked databases. if that’s the case you may lose some transactions
your database documentation should have this information.