Backend migration

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Overview of a Basic Upgrade

  • Review the Release Notes e.g. 0.27.4 (don't forget to read the Release Notes of any skipped releases.)
  • Shut down all mythfrontend processes (on all hosts).
  • Shut down the mythbackend process, Master and Slave(s).
  • Back up the MythTV database.
  • Upgrade/install the new mythtv packages on all backend(s).
  • Upgrade/install the new mythtv packages on all frontend(s).
  • Run mythtv-setup on the Master Backend*. The database will automatically be upgraded.
  • Exit mythtv-setup.
  • Start the backend process.
  • Start the frontend process on your frontend system(s) .
*Users with headless backends, type: ssh -l mythtv -Y <BackendHost> mythtv-setup

Building a new backend to replace an existing machine

If you want to build a new master backend, and test it before taking it into service, then follow these steps:

  • Build the machine, install the OS, etc.
  • It is suggested that unless you have a dedicated network on which to test the new machine, to give it a new IP address and hostname.
  • Test the machine.

When you are ready to press the machine into service as the master backend:

  • Stop all frontend and backend processes on all machines.
  • Back up the database on your existing master backend.
  • Copy the resulting backup file to the new machine.
  • Restore the database on the new machine. Depending on how your distribution initialises the database upon installation of the backend, you may need to use the procedure for replacing the database by the backup.
  • Before doing anything else, if you used a different hostname for the new machine, change the hostname of the master backend.
  • Start up mythtv-setup and also change the master backend IP address on the General Settings page.
  • Copy all media (recordings, videos, music, etc) from the old machine to the same directory structure on the new machine.
  • Modify /etc/mythtv/mysql.txt and /etc/mythtv/config.xml on all machines to point to the new database server.
  • If your frontends NFS-mount anything from the master backend, change those mounts to point to the new backend.
  • Start the master backend and all mythtv processes on all machines.

Retiring an old backend

3 steps are required to (properly) retire a backend system

  • If you still have access to the to-be-retired backend system:
    • Start mythtv-setup on the to-be-retired backend system and go to Capture Cards and select "Delete all capture cards on <hostname>" (use the "on <hostname>" option so you leave your cards on the other backends defined).
    • While still in mythtv-setup on the to-be-retired backend system, go into Storage Directories, and Delete each Storage Group on the to be retired host (select the group and hit DELETE (by default, 'D')). If you've configured your system such that you've only defined Storage Groups on the master backend (and did not override any Storage Group directory lists on remote backends), this step will be unnecessary. If you want to be sure, or you would like to redo your Storage Group definitions to make sure they're only specified on the master backend, perform this step on the master backend system, as described in the "If you no longer have access to the to-be-retired backend system" section, below.
  • If you no longer have access to the to-be-retired backend system (the host died/broke/...):
    • Start mythtv-setup on any host and go to Capture Cards and select "Delete all capture cards" (not "Delete all capture cards on <hostname>").
    • In mythtv-setup on the master backend system (it must be the master backend system), go into Storage Directories, and Delete each Storage Group (select the group and hit DELETE (by default, 'D')). Be sure to delete the actual storage group and not just the storage directories. If you've configured your system such that you've only defined Storage Groups on the master backend (and did not override any Storage Group directory lists on remote backends), this step will be unnecessary. Note, though, that performing this step cannot do any harm, even if you forget to re-create any custom Storage Groups.
      • This will delete all Storage Groups and Storage Group directory lists from all hosts. Then, re-create the Storage Groups and re-define directory lists. You do not need to create all the same custom Storage Groups you previously had as long as you put all the same directories into what Storage Groups you do create. Make sure that you create any special "built-in" Storage Groups you were using (such as Videos, Trailers, Screenshots, DB Backups, or ...) by using the provided buttons (such as "(Create Videos group)").
  • Update your database to tell mythbackend that a new host now owns the recordings from the to-be-retired backend host:
mysql -umythtv -p mythconverg -e "UPDATE recorded SET hostname = 'new_hostname' WHERE hostname = 'old_hostname';"

The Database Backup and Restore tool has a utility for migrating a backend from one hostname to another, but it is a blanket change for all settings and hardware as well. It cannot be used to just shift recordings. As always, a database backup before doing any manual database manipulation is recommended. Note that this is only required for recordings. The location of any video content will be updated automatically based off a matching hash, with no loss of metadata, next time a Scan For Changes is triggered from the Watch Videos menu.