My mythTV Backedend is an Intel quad core 2.4 with 4GB of G.Skill RAM. A vanilla GigaByte motherboard in a fairly nice looking case with 2TB of disk. I use a pair of HVR-2250′s to record digital cable signals and I’m generally pretty happy with the whole solution – as is my family.
For the last 2-3 months I’ve been noticing segfaults, abnormal process terminations and in some cases the complete MythTV stack terminates, leaving my wife without her regular Grey’s Anatomy or House, leaving me with a headache and a nagging suspicion that I need to fix the platform.
Any guesses on what’s going on?
Yep, faulty RAM. The backend is positioned in a warm and dry basement but to debug the system I have to disconnect the hardware and move the system into my home office where I have access to monitors, keyboards, benches and other tools.
I pulled the RAM, both sticks and tested each stick independently using Memtestx86. The first stick passes perfectly but the second stick fails within 5 seconds. Yep, that would do it. The problem is that I suspect I now have corrupt filesystems so I’m going to have to wade through some of the ext4 fsck support tools to validate/recover the system.
Luckily I have some spare disks so if push comes to shove and I have to extract the good recordings from the system onto spare disks before re-creating the filesystems, then that’s possible.
I like the fact that with ext4 I can delete 8GB recordings in a faction of a second, I don’t like the fact ext3 takes 20-30 seconds to perform the same transaction. Now I’m starting to wonder how reliable my long term recordings are, and how much faith I have in ext4 generally! I like to record a lot of shows to cover us over the summer ‘shortage’. I don’t go back an check these. If these shows are bad or marginally corrupt then I’ll be an unhappy camper.
Lessons learned? When your system starts segfaulting don’t wait a couple of months to deal with it, fix it else risk trashing your filesystems.
The only thing worse than playing ‘file system recovery’ is a wife constantly reminding you that she missed her weekly dose of ‘So you <blah> you can <whatever>’. On the other hand, it’s perhaps an ‘accidental’ way of dropping cruddy shows. 
Troubles recording TV = unhappy family.
I should go and get on with fixing it…. later.
