[mythtv-users] Rebuilding a FE/BE system (the stupid way)

[William Powers]

Jan 17, 2013, at 4:57 AM, Science Technician <SCITECH at combebank.kent.sch.uk> wrote:

>> So any advice on a good partitioning tool for Fedora that will allow me to do that would be great. I see there are several in the package installer but which one to choose.

Ok, from the data you provided (although different than what you wrote) partition sda1 is the boot partition and is about 200M. Sda2 and sdb1 are the LVM physical volumes in your volume group and they contain both your recordings and the bulk of your OS.  This is the 'less desirable' configuration I described in my earlier note.  Frankly, I personally do not know of any way to get completely rid of LVM from here unless you can fit everything on the SMALLER hard drive or you have temporary access to a third hard drive big enough to hold all of your recordings.

What I would do in your position, based on what you have said, is first do the database backups described earlier as well as record the LVM mounting line from /etc/fstab.  Then I would execute the necessary commands to tell LVM to remove sda2 from the Volume Group.  This will cause LVM to move EVERYTHING on sda2 to sdb1 so be certain it will all fit before you start.

The partition numbering might be different on sda if there is a swap partition.  Be careful you know which is which.

I will not even attempt to tell you what LVM commands to use from memory. I suggest the LVM howto or just Google.

That will take a while and, once complete, you can proceed with installing the new OS. Disconnect the sdb drive so you don't get confused and wipe it by mistake.  As part of the install, repartition sda. I would leave sda1 alone so you could go back if something goes wrong.  Delete the big sda2 partition and create a 20G or so partition for the new OS (root). Don't let the installer use sda1 as a boot partition.  If you feel you must have a boot partition, create a new one. Lastly, use the remaining space on sda for a big partition for recordings, select the file system of you choosing and a mount point wherever you want your recordings to live.  Then install.

Since you disconnected sdb, the installer will not find it and add it for you.  So, once the install is complete, shut down, reconnect sdb, boot and add a mount line for the Volume Group.  Do not copy the old mount line verbatim as it was probably mounted as /root.  Instead, mount it in the same place you mounted the other partition for recordings.

You should now have two partitions for recordings mounted some place like /mnt or /media or whatever.  One will be a simple partition that will be empty and the other will be an LVM Volume Group with a single physical volume which will be partially full. 

At some point, now or later, you may want to go into the volume group and manually delete all the OS bits, but be very, very careful when doing so.

Lastly, install MythTV.  After installation, but before restoring the database, as part of MythTV- setup, you will set up your Storage Groups. Unless you have a reason to do otherwise, I would stick to the single Default storage group and add the full pathname of both recordings folders to the default group.

Note:  It is very important not to store recordings in the root folder of any partition. Create at least one sub-folder and use that.  The reason is explained in the MythTV docs and on the Wiki.  Good luck and be careful!