:q1

When changing Mysql dirs, and using a symbolic link path for "innodb_log_group_home_dir" (which does not end with a trailing "/") makes SST fail. For example:

Symbolic link:

ln -s /mysqldb/innologs/ /var/lib/mysql/innologs

Using:

1. innodb_log_group_home_dir = /var/lib/mysql/innologs/ # does work

2. innodb_log_group_home_dir = /var/lib/mysql/innologs # does NOT work

The error comes because SST does not remove ib_logfile from a previous execution, i.e the following does NOT show on mysql log:

removed ‘/mysqldb/innologs/ib_logfile1’

removed ‘/mysqldb/innologs/ib_logfile0’

And innobackup.move.log

innobackupex version 2.3.10 based on MySQL server 5.6.24 Linux (x86_64) (revision id: bd0d4403f36)
Error: Move file ib_logfile0 to /var/lib/mysql/innologs/ib_logfile0 failed: Destination file exists

In order to reproduce, follow this steps:

1. Pre-requisite:

1. ib_logfiles MUST exist on innodb_log_group_home_dir , as what is fail is the removal for a new SST

1. Create custom dirs and symbolic link:
   _{mkdir /mysqldb/
   mkdir /mysqldb/data/
   mkdir /mysqldb/innodata
   mkdir /mysqldb/cluster/
   mkdir /mysqldb/innologs/
   chown mysql:mysql -R /mysqldb/
   ln -s /mysqldb/innologs/ /var/lib/mysql/innologs
   chown -h mysql:mysql /var/lib/mysql/innologs/}

# Add to config:

_{[mysqld]
datadir = /mysqldb/data
innodb_data_home_dir = /mysqldb/innodata
wsrep_data_home_dir = /mysqldb/cluster}

1. Check with both parameters:

1. innodb_log_group_home_dir = /var/lib/mysql/innologs/ # does work

1. innodb_log_group_home_dir = /var/lib/mysql/innologs # does NOT work

1. Stop Mysql, remove grstate to force SST and restart Mysql

1. ib_logfiles must exist on the new directory for this to fail, so you need to execute twice or manually copy the files

_{systemctl stop mysql
rm -fr /var/lib/mysql/grastate.dat
rm -fr /mysqldb/cluster/grastate.dat}

_{systemctl start mysql}