I am currently using Mythbuntu 14.04 and want to upgrade, but I need to change partition layout, so I need to do a clean installation. However, I want to retain the recorded programs. 14.04 is using mythtv 0.27, whereas 16.04 uses 0.28 and documentation tells I should backup database before upgrading version. Can I restore the backup in 16.04 even if it is done by different version?
Yes, I have done this when I moved from Mythbuntu 14.04 to Mythbuntu 16.04. I had the database backup (mythconverg-1317-20160708233351.sql.gz, automaticaly generated by the Mythbuntu 14.04 system) and the recordings on one drive, and then I installed Mythbuntu 16.04 on a different drive. I mounted the recordings in the same place in the filesystem as before. I stopped the backend and restored the database onto the Mythbuntu 16.04 system from the backup from the Mythbuntu 14.04 system.
When I launched the frontend it displayed this message:
Warning: MythTV wants to upgrade your database, for the Music schema, from 1020 to 1024
I consented. After that it all worked fine, except when I went into Mythweb, when I got an error
!!NoTrans: SQL Error: Expression #3 of SELECT list is not in GROUP BY clause ...
As described at https://code.mythtv.org/trac/ticket/12713 I added the following lines to the end of /etc/mysql/conf.d/mythtv.cnf and it solved the problem:
I don't believe so. You'll have to upgrade 14.04 to 0.28 first, then backup the database, install 16.04 and then restore.
It's possible that you can restore a 0.27 database to a 0.28 system and the backend will attempt to upgrade that when started, but I've not tested this.