Questions concerning Migration Tool

Discussion in 'Plugins/Modules/Addons' started by stefanm, Jul 5, 2016.

  1. stefanm

    stefanm New Member HowtoForge Supporter

    Hi,
    so far I have been reluctant to update our servers to Jessie, but I am in great hope that your migation tool will provide a way that spares me of some of my headaches with the move.
    I only have two minor questions left: Currently we have two servers s1 and s2 (running wheezy and ispconfig 3.53) which are replicated via ispconfig,mysql-replication, csync. The main server is s1 (s2 is actually a backup in case s1 is gone, access is done via a failover ip).
    To replace the two servers with new servers running jessie and the latest ispconfig, I assume I would set up the new servers s3 and s4 and then migrate from s1 to s3 and let the replcation do the rest. Is that right?
    The servers carry around 100 websites and 200 GB user data, so a migration would presumably take some time. Does the migration tools always migrate everything or is it possible to migrate step by step (per customer, ...)? How do I migrate changes that occured while the migration script was running?
    Many thanks for your help!
     
  2. till

    till Super Moderator Staff Member ISPConfig Developer

    yes.

    It migrates everything.

    The tool runs in 2 phases.

    First it creates the websites, email accounts etc. on the target server. During this step, a shell script gets created which will do the data migration in the second phase. you copy this shell script to the target server and start it there, it will then copy over all data with rsync and migrate the content of the databases and emails. This data copy script can be run more than once.

    So you just have to ensure that no changes were made in the ispconfig interface by setting it to maintenance mode. Data changes can be resynced.

    So the normal migration procedure is this:

    1) Let the script create the websites, mail accounts etc.
    2) Do a first data sync.
    3) Test the new server.
    4) Resync the data and switch over the services to the new server, you can redirect the traffic with iptables so the switch can be done instantly without having to wait for dns changes.
     
  3. stefanm

    stefanm New Member HowtoForge Supporter

    Hi Till,
    thanks a lot for the detailed explanation!
    One last question:
    When proceeding to step 4: Before doing the "final" resync, I guess I have to stop the services on the source server, so no new mails are accepted, no new web sessions,...?
    If I run the resync again after the the switch to the new server has been done (to be sure that there are no updated data are left on the source server), that could collide with new data in the target server? Or can the migration tool merge data from source and target?
    Thanks again for your help!
     
  4. till

    till Super Moderator Staff Member ISPConfig Developer

    You can either stop the services or redirect them to the new server. The data is migrated with rsync and the mysql data is dumped on the old server and then imported into the new one. As far as I know, mysqldump does not support it to merge data, so it will replace the data.
     
    stefanm likes this.
  5. stefanm

    stefanm New Member HowtoForge Supporter

    Thanks a lot for your help! Sounds great!
     

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