Comment 3 for bug 1671437

I seem to be having this same issue as well:

$ innobackupex --version
innobackupex version 2.4.6 Linux (x86_64) (revision id: 8ec05b7)

$ mysql --version
mysql Ver 15.1 Distrib 10.2.4-MariaDB, for Linux (x86_64) using readline 5.1

# innobackupex --apply-log /root/my-backup/2017-03-24_12-12-54
170324 12:23:40 innobackupex: Starting the apply-log operation

IMPORTANT: Please check that the apply-log run completes successfully.
           At the end of a successful apply-log run innobackupex
           prints "completed OK!".

innobackupex version 2.4.6 based on MySQL server 5.7.13 Linux (x86_64) (revision id: 8ec05b7)
....
....
....
InnoDB: Progress in percents: 1InnoDB: File './ibtmp1' size is now 12 MB.
InnoDB: 96 redo rollback segment(s) found. 1 redo rollback segment(s) are active.
InnoDB: 32 non-redo rollback segment(s) are active.
InnoDB: page_cleaner: 1000ms intended loop took 492004ms. The settings might not be optimal. (flushed=0 and evicted=0, during the time.)
InnoDB: page_cleaner: 1000ms intended loop took 492004ms. The settings might not be optimal. (flushed=0 and evicted=0, during the time.)
InnoDB: xtrabackup: Last MySQL binlog file position 332937698, file name ./binlog.000001

xtrabackup: Recovered WSREP position: 00000000-0000-0000-0000-000000000000:-1
xtrabackup: starting shutdown with innodb_fast_shutdown = 1
InnoDB: FTS optimize thread exiting.
InnoDB: Starting shutdown...
 2 3 4 5 6 7InnoDB: Waiting for 1 active transactions to finish
 8InnoDB: Waiting for 1 active transactions to finish
 9 10InnoDB: Waiting for 1 active transactions to finish
 11 12InnoDB: Waiting for 1 active transactions to finish
 13 14InnoDB: Waiting for 1 active transactions to finish
 15InnoDB: Waiting for 1 active transactions to finish
 16 17InnoDB: Waiting for 1 active transactions to finish

It's now been sitting like this (up to #81) for about an hour.