I am trying to start a second mysqld instance to restore data from backup (innoDB).

Following the manual I put together this:

cd $P
mkdir tmp
touch mysql.log
chown -R mysql:mysql .
# mysqld v5.0
mysqld --console --port=3399 --socket=/var/run/mysqld/mysqld.sock --datadir=$P /
   --pid-file=$P/mysqld.pid --log=$P/mysql.log --log-bin=$P/bin.log /
   --log-error=$P/error.log --tmpdir=$P/tmp --innodb_force_recovery=6 

and ended up crashing my running instance.

Question is: How do I create a second mysqld instance using the backup folder?

  • You need to look in the logs that the crashed instance wrote. – user9517 Jul 2 '14 at 11:30
  • @Iain Well, it did not write any logs. I had some console output but I lost that while I restored the main instance. Can't try that again. That's why I am here to make it save this time. – PiTheNumber Jul 2 '14 at 11:37
  • $P/error.log ? And without logs we can only guess – user9517 Jul 2 '14 at 11:39
  • @Iain no error.log and mysql.log is empty. I don't know why... – PiTheNumber Jul 2 '14 at 11:40

Yes I would say you need a second socket. You can create one it using mkfifo - but maybe MySQL should recreate it on its own.


Try this:

chown -R mysql:mysql $P
# mysqld v5.0
mysqld --port=3399 --socket=$P/mysqld.sock --datadir=$P \
    --pid-file=$P/mysqld.pid \

If it does't start, check $P/error.log why

  • you're saying the instance is crashing. I wonder how backup was taken and how do you know it's crashing – akuzminsky Jul 2 '14 at 14:03
  • Thank you I will try that. I know the current instance was crashing because the website went down with DB error and mysqld restart failed. After I kill -9 mysqld it did start again. What you are chainging is mainly to remove --console and --innodb_force_recovery, right? Changing log path and tmp probably does not hurt I guess. – PiTheNumber Jul 2 '14 at 14:55
  • 1
    right, you don't need --console as long as you logging to a file. innodb_force_recovery has its use but not applicable in your case. The major problem was a socket potentially at the same destination as for the main instance and you chown-ed tmp directory, not $P – akuzminsky Jul 2 '14 at 16:30

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