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PostPosted: Sat Jul 06, 2013 1:51 pm 
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Joined: Sun Apr 30, 2006 7:49 pm
Posts: 37
Location: Ottawa
I have successfully completed a transition from mythbuntu to LinHES R8. There were a couple of difficulties, so I'm reporting here to help anybody else who might want to go through it.

Initial configuration was a mythbuntu installation on a 60GB SSD. Two partitions, one /, the other swap. Three large hard drives provided recording space on sdb, sdc, and sdd.

I downloaded R8-02-11-2013.iso and burned a CD.

After performing a complete backup, I booted the CD. I was offered the choice between upgrading and installing. I figured that the 'upgrade' option wouldn't work very well when faced with a completely different distribution, so I tried the install. It wanted me to create multiple partitions, one for /, one for /home, one for the database, and one for the recordings. I figured I could start from there, and then tweak the configuration manually. I realized, however, that there were limits on how large I could make /, and on how small I could make the recordings directory. Since I wasn't planning on using a recordings directory on the SSD, I thought I'd try to see what the upgrade option did.

I switched to the upgrade option. It warned me that it couldn't figure out the previous version, and then I gave it permission to keep going. It claimed to perform the install, but when I booted the box, it immediately powered itself down. Using the boot CD, I edited the grub configuration to turn off the splash and get verbose kernel output. Things still went by very quickly and then the computer turned off, so I used my cellphone to take video of the bootup screen and was able to read what was there just before it went away. The files /etc/runit/1, /etc/runit/2, and /etc/runit/3 were not present, which is a fatal error for runit, and causes it to invoke a powerdown. This is probably because of the unexpected "upgrade" starting point.

So, next, I used the boot CD, and I blanked the SSD so that there would be no confusion. I told it to do a fresh install. Once that completed, I used the boot CD to start inspecting what was there. I copied all of the files from the 3 partitions (/ /home db) into a file tree in a directory on one of my big hard drives. Then I used fdisk to repartition sda into two partitions again (I know the database ought to go in its own partition, but at this point I didn't want to try anything too challenging). I formatted one for ext3, the other for swap. Then I edited the fstab, removing the mount commands for /home, the database, and the media drive, and adjusting the UUIDs appropriately, as I had reformatted / and swap. Then I put in the fstab entries for the 3 large hard drives from the backup's version of fstab. I also deleted the symbolic link at /myth and replaced it with a directory, as that is the mount point for one of my large hard drives.

After this, I was able to reboot into the LinHES installation on the SSD. I chown-ed some files that had different UIDs between mythbuntu and LinHES, and did a few little tweaks and fixups related to my personal customizations. The system can now make play and make recordings.


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PostPosted: Sat Jul 06, 2013 2:58 pm 
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Joined: Sun Sep 05, 2004 7:06 pm
Posts: 690
First, welcome to R8 it's a really great product. I'm not sure if you're are aware of Storage Groups but they are fully supported in Linhes. Since R8 is major upgrade everyone has had the chance to restructure their setups. Ideally users now install a small drive or ssd for boot and then put all there other drives into the storage group for recordings. Then myth can record on any drive and you don't run out of space. It's alot easier to just run the cd install on your boot drive and then setup the storage group.

Here is the migration doc for Linhes for reference. It also would apply to mythbuntu since R8 is more or less scratch

http://linhes.org/projects/linhes/wiki/ ... _R7X_to_R8


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PostPosted: Sat Jul 06, 2013 4:47 pm 
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Joined: Sun Apr 30, 2006 7:49 pm
Posts: 37
Location: Ottawa
Yes, I was using storage groups on LinHES before I moved to mythbuntu, and still use them now that I'm back.

I'll point out that I omitted a step in my description of the transition. Once I had everything ready to go, I restored my database from its backup with # mysql mythconverg < dbdump.sql

Now, why did I go through all this? I used Knoppmyth starting around R5, several years ago. I went up to LinHES. Then, about 8 months ago, I was feeling the pain of running a 32-bit system. While the hardware was 64-bit, the LinHES installation CD was 32-bit. The most obvious place this caused difficulty was in my transcoding jobs. I had some scripts for H.264 transcoding that ran at about 2 fps on 32-bit, but 20 fps on 64-bit. For a while, I was using an offload engine for transcoding, tossing the .mpg files over the network to a machine with a 64-bit version of ffmpeg, and then copying them back. So, I decided I wanted to upgrade the box to 64-bit. I expended some effort to try to figure out how to compile a 64-bit LinHES system, but in the end could not figure out how to do it. I had the git repository, and I am no stranger to compiling binaries, but my lack of familiarity with the innards of Archlinux was enough that I just decided to swap in a mythbuntu 64-bit disc instead.

Why did I return? Mythbuntu always feels a bit like an ubuntu box running mythtv as an application. That's what it is, of course, but Knoppmyth/LinHES feels like an appliance built around MythTV. Mythbuntu would occasionally pop up a dialogue box about package upgrades in the middle of us watching a show. There were also frequent audio glitches that I had never encountered before on LinHES. The sound would briefly cut out. It wasn't in the source, if I rewound the file and played through the glitch again, it wasn't there anymore. Between these annoyances, I decided I'd go back to LinHES, now that there is a 64-bit .iso available.

In fact, this transition was probably one of the smoothest upgrades I've had. In the past, upgrading with a CD has always been a several-hours long affair.


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PostPosted: Sat Jul 06, 2013 5:36 pm 
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Joined: Sun Sep 05, 2004 7:06 pm
Posts: 690
Well then welcome back!

In the Linhes Service Menu you can find Samba, NFS, and MythWelcome

There are also packages for XBMC, Chromium, and Flash Plugin that can be accessed via Pacman (no more apt-get)
Also there is a small update to R8.02 via
Code:
Pacman -Syu


Nvidia VDPAU is build right in to R8
http://en.wikipedia.org/wiki/VDPAU

For Transcoding HD have a look at Handbrake


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PostPosted: Sun Jul 07, 2013 11:52 am 
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Joined: Fri Jun 11, 2004 7:58 am
Posts: 507
Just a word of warning, depending on how the database was restored it's very possible that any attempt to use the service menu will mess up your system.
The service menu stores all it's values in the DB, and if they are not present then they revert to default values which may not fit your system.
It's possible they can be restored from /usr/MythVantage/tmplates/setting/syssettings but using that will overwrite so other myth values that were imported.

Also by changing the partition layout, the system can no longer be updated via CD. The CD upgrade process makes some assumptions about partition layout, and doesn't handle that type of error very well. Just something to keep in mind.


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