innobackupex Incremental backup fails on LOCK BINLOG FOR BACKUP...

Executing an incremental backup on my database and it failed with the following trace. Any clues to what is wrong.

Backup Version is: InnoDB Backup Utility v1.5.1-xtrabackup; Copyright 2003, 2009 Innobase Oy
and Percona LLC and/or its affiliates 2009-2013. All Rights Reserved.

This software is published under
the GNU GENERAL PUBLIC LICENSE Version 2, June 1991.

Get the latest version of Percona XtraBackup, documentation, and help resources:
http://www.percona.com/xb/p

Server Version is: Server version: 5.6.21-70.0 Percona Server (GPL), Release 70.0, Revision 688

Command is: innobackupex --compress --incremental /usb/ariel/innobackupex/mysql --incremental-basedir=/usb/ariel/innobackupex/mysql/2015-01-14_05-51-30

Log Trace is:
innobackupex: Backing up files ‘/srv/mysql//annotation_service/*.{frm,isl,MYD,MYI,MAD,MAI,MRG,TRG,TRN,ARM,ARZ,CSM,CSV,opt,par}’ (10 files)
innobackupex: Backing up file ‘/srv/mysql//entrez/db.opt’
innobackupex: Backing up file ‘/srv/mysql//entrez/gene.frm’

log scanned up to (8048683632701)
innobackupex: Backing up file ‘/srv/mysql//entrez/synonym.frm’
150121 10:38:01 innobackupex: Finished backing up non-InnoDB tables and files

150121 10:38:01 innobackupex: Executing LOCK BINLOG FOR BACKUP…
DBD::mysql::db do failed: MySQL server has gone away at /usr/bin/innobackupex line 3036.
innobackupex: got a fatal error with the following stacktrace: at /usr/bin/innobackupex line 3039
main::mysql_query(‘HASH(0x1df0d20)’, ‘LOCK BINLOG FOR BACKUP’) called at /usr/bin/innobackupex line 3501
main::mysql_lock_binlog(‘HASH(0x1df0d20)’) called at /usr/bin/innobackupex line 2000
main::backup() called at /usr/bin/innobackupex line 1592
innobackupex: Error:
Error executing ‘LOCK BINLOG FOR BACKUP’: DBD::mysql::db do failed: MySQL server has gone away at /usr/bin/innobackupex line 3036.
150121 10:38:01 innobackupex: Waiting for ibbackup (pid=4074) to finish

As a follow-up I found that my SQL server actually restarted in the middle of this. I don’t know if it was b/c of the backup or something else. The mysqld log file just shows the sever rebooting, no other error messages.

Hi,

Can you try to run backup again and check if this error is reproducible or not? If yes, then this might be a bug.