Troubleshooting:Mythfilldatabase IO bottleneck
When updating a significant number of channels mythfilldatabase and MySQL will cause enough disk or I/O activity to interfere with recordings, playback, and live tv. The interference can cause recordings or playback to become garbled and may cause the backend to cancel the recording or stop entirely.
There are two known resolutions to this problem. You can choose to either reduce the number of channels you subscribe to, or you can migrate your MySQL database to another machine or hard disk.
Reduce Channel Listings
By far, the simplest method of resolving the issue is to reduce the number of channels mythfilldatabase updates. If you are using DataDirect you can manage this from the subscription site. I do not have any experience with XMLTV, but you will probably need to check both your configuration and service provider to reduce the updated channels.
If you must keep all of those channels, you may want to migrate your MySQL server. You might consider running MySQL on another server if you have one to spare. You can move the mythconverg database by backing up from your current server, and restoring on the new one.
Alternatively, you could keep your MySQL database on separate hard disk. I recommend that you keep the database hard disk on a separate bus (ATA/IDE or SATA) to ensure that the bus is not saturated with requests as well as your hard disk. Changing the structure of your installation is distribution dependent. However, the MySQL files can be copied and moved so long as mysqld is not running. Check your linux distribution for more information.