[mythtv-users] write took a long time log messages

[Dave Oxley]

I've recently built a new server which is used for amongst other things
as a mythtv backend. I'm getting these messages output in the log and I
don't understand why. Are these messages actually an issue?

Aug  1 15:54:21 baldrick mythbackend[38856]: W TFWWrite
ThreadedFileWriter.cpp:499 (DiskLoop)
TFW(/srv/media/tv/1022_20120801154300.mpg:68): write(60536) cnt 15 total
874012 -- took a long time, 1412 ms
Aug  1 15:54:33 baldrick mythbackend[38856]: W TFWWrite
ThreadedFileWriter.cpp:499 (DiskLoop)
TFW(/srv/media/tv/1022_20120801154300.mpg:68): write(57716) cnt 12 total
684508 -- took a long time, 1233 ms

The recordings volume is 512GB XFS on a raid 6 mdadm array. It's mounted
with allocsize=512m, 57GB free, and fragmentation currently looks like this:
actual 595, ideal 534, fragmentation factor 10.25%
Everything except /boot is on the same raid 6 array which is 4 3TB
Seagate disks and the partitions are managed via LVM. stripe_cache_size
is 32768. dd of a 20GB file gives a write speed of about 290MB/s and
hdparm a read speed of about 270MB/s. The mysql database is on a ext3
volume, and the rest of the OS is on ext4 volumes. The server has a
single Xeon E5-2620 with 16GB ram. Does anyone have any ideas what I can
look at to resolve this?

Cheers,
Dave.