[mythtv-users] Moving frontend/backend to a new machine

[Rich West]

On 12/19/2013 03:19 PM, Gary Buhrmaster wrote:
> On Thu, Dec 19, 2013 at 8:02 PM, Rich West <Rich.West at wesmo.com> wrote:
> ....
>> Not lucky at all.
> Perhaps you have enough experience to know better, and
> know what to do, and not to do, but posting such advice on
> a forum that will be archived, and searched in the future,
> and used without fully understanding all (and more) of
> the following is just asking for trouble down the road.
>
> For anyone who is not a DBA, use the supplied scripts.
> It is just the right advice for most.
>
> Potential issues by copying binary files (not complete,
> just what I thought of):
>
> * If the mysql versions are different, you may have to
>   perform specific upgrade steps (which may require
>   reading all release notes).
> * Different versions may have initialized with differing
>   system files.  Replacing those files may result
>   in brokeness.
> * The db engines (available/defaulted to) may be
>   different.  You may not be able to read the data.
> * If you are migrating to/from mysql/mariadb (and
>   if you are not aware, most distros are changing),
>   you may need to perform specific migration steps.
>   (and while mysql/mariadb currently are mostly
>   compatible, even at the file level, both have indicated
>   future incompatible changes may occur).
> * If the system endianess is different, most likely the
>   database will be broken by moving binary files.
> * If the mysql configuration specifies different locations
>   for various directories and files you will end up with
>   various brokeness
> * Not copying the appropriate my.cnf (or my.cnf.d)
>   configuration options may result in brokeness.
>   Copying those files without understanding may
>   also result in brokeness.
>
> Yes, an experienced DBA, with years of failing to
> follow all of those steps (and lots more), and learning
> from each, can just "copy files".  For everyone else,
> use the scripts.

Ya know I said that, right..?  "The mythconverg_backup.pl and
mythconverg_restore.pl scripts are a good way to go as well, especially
if you don't have a lot of linux experience."  While I disagree with
your assessment (it really isn't that complicated of a process IMHO), I
certainly didn't mean to offend, but it seems I somehow inadvertently have.

Anyhow... my mistake was making the assumption that the question was
posed by someone staying within the same distribution and answering in
too general a fashion based upon my experience with mythtv (kinda
thought that's what the list was about).  Bad me.


Getting back on track here, other items for the original requester to
consider when moving the frontend/backed to a new machine are to:
1. maintain the same path(s) to your recording storage or be prepared to
update the entry in your storage groups within mythtv-setup
2. Since the machine is a frontend-backend system, keep in mind that
devices *may* likely change.  Recording devices, USB devices, network
devices, etc.
3. I had been only referencing handling the backend.  Keep in mind that
the frontend piles a lot in the .mythtv folder, like coverart and such
(unless you changed the path to point elsewhere).  If the path changes,
you will not get your coverart as you expect.
4. If you choose to copy data over vs moving over your hard disk, make
sure you grab all of your coverart. :)

There's more, but you get the idea.  Moving from one system to another
isn't an insurmountable task, but it does take some perseverance and
general under-the-hood linux know-how.  And you always have the list
here to help in a pinch.

-Rich