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Forensics: Close to death experience
http://forum.linhes.org/viewtopic.php?f=6&t=16441		 Page 1 of 1
Author:  cahlfors [ Tue Sep 11, 2007 12:54 pm ]
Post subject:  Forensics: Close to death experience
In case someone is interested in forensics:

I just got back in business from a situation where the box had a file missing. Rebooting it resulted in the backend not starting at all. An hour before the girls' favorite show! :cry:

It turned out that /myth had its ownership/group automatically changed from mythtv/mythtv to root/root. :shock: By what? This resulted in /myth/tv/nfslockfile.lock was inaccessible for permissions reasons and the backend not starting at all. There was also a db error (causing the file missing error above), which I thought was the trouble and fixed it per tjc:s excellent guide in the hints&tips section.

Here's an excerpt from /var/log/mythtv/backend.log (� denotes our special scandinavian chars - they are not errors):
Code:
2007-09-11 18:00:33.723 Expiring V�ra v�rsta �r "Del 232 s�song 10" from Tue Se$
2007-09-11 18:00:42.801 DB Error (Recorded program delete recordedseek):
Query was:
DELETE FROM recordedseek WHERE chanid = '1006' AND starttime = '2007-09-11T17:5$
Driver error was [2/145]:
QMYSQL3: Unable to execute query
Database error was:
Table './mythconverg/recordedseek' is marked as crashed and should be repaired
2007-09-11 18:26:34.367 AutoExpire: ERROR: Could not calculate free space for /$
2007-09-11 18:28:34.411 AutoExpire: ERROR: Could not calculate free space for /$
2007-09-11 18:28:34.414 AutoExpire: ERROR: Could not calculate free space for /$
2007-09-11 18:28:34.415 AutoExpire: ERROR: Could not calculate free space.
2007-09-11 18:30:34.469 AutoExpire: ERROR: Could not calculate free space for /$
2007-09-11 18:32:34.525 AutoExpire: ERROR: Could not calculate free space for /$
2007-09-11 18:33:34.548 AutoExpire: ERROR: Could not calculate free space for /$
2007-09-11 18:33:34.550 AutoExpire: ERROR: Could not calculate free space.

etc a bunch of lines and (oh, yeah, it should be free space for /myth/tv) then
Code:
2007-09-11 18:48:34.919 AutoExpire: ERROR: Could not calculate free space for /$
2007-09-11 18:48:34.921 AutoExpire: ERROR: Could not calculate free space.
2007-09-11 18:49:43.588 MainServer::HandleAnnounce Monitor
2007-09-11 18:49:43.648 adding: Ludde as a client (events: 0)
2007-09-11 18:49:43.689 Preview Error: Previewer file '/myth/tv/1004_2007090921$
2007-09-11 18:49:43.690 MainServer: Failed to make preview image.
2007-09-11 18:49:44.926 MainServer::HandleAnnounce Monitor
2007-09-11 18:49:44.929 adding: Ludde as a client (events: 0)
2007-09-11 18:49:44.931 Preview Error: Previewer file '/myth/tv/1004_2007090921$
2007-09-11 18:49:44.932 MainServer: Failed to make preview image.
2007-09-11 18:49:46.491 MainServer::HandleAnnounce Monitor
2007-09-11 18:49:46.512 adding: Ludde as a client (events: 0)
2007-09-11 18:49:46.513 Preview Error: Previewer file '/myth/tv/1006_2007091117$
2007-09-11 18:49:46.514 MainServer: Failed to make preview image.
2007-09-11 18:49:46.904 MainServer::HandleAnnounce Monitor

All these errors (and still more) for ownership reasons.
Fixing the database didn't fix the problem.
Removing the nfslockfile.lock didn't fix the problem.
Changing the ownership/group of /myth did fix the problem and the lost file belonging to a recording was back again.

Thank heavens for this forum - it enabled me to find the clues I needed and be back in less than an hour :!:
Or I would have been in the next episode of "Midsomer murders". :wink:

/Chris
Author:  mihanson [ Tue Sep 11, 2007 1:13 pm ]
Post subject: 
Is your box exposed to the internet in any way? SSH, HTTP, etc?
Author:  cahlfors [ Thu Sep 13, 2007 12:40 pm ]
Post subject: 
Actually, yes!

I am using MythWeb set up per the securing MythWeb instructions on the Wiki (htdigest), using http and a reasonable password. However, my apache daemon keeps stopping, so I am currently in the process of redoing it per these instructions instead: http://mysettopbox.tv/phpBB2/viewtopic.php?t=15796&highlight=mythweb

When this happened, I was using the first setup. The myth box is behind a hw firewall/router.

/Chris
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