[mythtv-users] Slow deletes were causing backend to hang and/or cause seg faults

Mike Perkins mikep at randomtraveller.org.uk
Sun Jan 4 14:49:18 UTC 2009


Kenan Ezal wrote:
> This is continuation of the topic found here:
> 
> http://mythtv.org/pipermail/mythtv-users/2008-December/242458.html
> 
> I thought that a new title would be beneficial to clarify the cause of my
> problems and maybe help others.
> 
> My system information is: Linux MythTV2 2.6.27.5-41.fc9.x86_64 #1 SMP Thu Nov
> 13 20:29:07 EST 2008 x86_64 x86_64 x86_64 GNU/Linux Dual core CPU E2180 @
> 2.00GHz with 3.9GiB
> 
> My video partition is a RAID 5 with an ext3 filesystem.
> 
> I discovered within the last couple of days that the cause of my problems
> outlined in the original post (backend hanging/seg faults) were due to "slow
> delete" being turned on. Once I turned slow deletes off my problems went away
> and my system became stable.
> 
> Long story short, I become convinced after logging using the "-v all" option
> for both the frontend and backend. While I have not looked into the actual
> code, I gathered from the log that once you mark a program for slow delete it
> gets placed into a database for in-use files, and then gets taken out and put
> back into it again (multiple times) for some reason. Then the log just
> outputs the following sequence forever:
> 
> 2008-12-30 23:49:54.111 MythEvent: SCHEDULE_CHANGE 2008-12-30 23:49:54.145
> write -> 16 45      BACKEND_MESSAGE[]:[]SCHEDULE_CHANGE[]:[]empty 2008-12-30
> 23:49:54.150 write -> 21 45      BACKEND_MESSAGE[]:[]
> 
> I'm suspecting an infinite loop with some condition never being satisfied.
> Maybe the system is waiting for a confirmation that the slow delete is
> finished? The file does actually get deleted from my filesystem, however.
> 
> I have edited logs if anyone is interested in looking at them. The original
> log was 370MB (just overnight)!
> 
As a data point, I'm using ext3 (not raid though) with slow deletes turned on 
and have not had any problems with my setup.

-- 

Mike Perkins



More information about the mythtv-users mailing list