Percona xtrabackup hangs indefinitely in apply-log phase

Hi All

I'm using Percona xtrabackup to backup a Percona 5.7 (MySQL 5.7) instance.

It has been working fine for about 2 years.

Here is what I execute for phase 1 of xtrabackup - the initial phase:

Code:innobackupex --user=root --password=xxx --parallel=4 --rsync /backup_todayand then for phase 2 - the apply-log phase

Code:innobackupex --apply-log --user=root --password=xxx --use-memory=2GB
/backup_todayIn phase 2 xtrabackup then gets stuck for, well, so far 16 hours, just endlessly outputting

Code:InnoDB: Waiting for 1 active transactions to finish
InnoDB: Waiting for 1 active transactions to finish
InnoDB: Waiting for 1 active transactions to finishfor tens of thousands of lines until I kill -1 the xtrabackup process.

A "show processlist" in the associated Percona 5.7 instance shows no running transactions, no locked transactions, or any other activity...

Any ideas what I can do to get xtrabackup to actually finish a backup?

Thx!