[mythtv-users] strange NFS problem

[Keith Gautreaux]

On Friday 13 February 2004 07:20 pm, Jack wrote:
> Hi everyone
>
> Finally got my Mythbox working.
> Very impressive piece of work!
>
> Using Myth 0.14 on Fedora 1
> Fileserver runs freebsd 4.8
>
> I store my recordings using NFS.
> Mounting line in /etc/fstab :
>
> 192.168.2.111:/muziek1  /mnt/nfs                nfs
> udp,rsize=8192,wsize=8192,hard,nfsvers=3
>
> This works fine with normal file copying...
>
> But NOT when using Myth:
> When A scheduled recording ends my network stays under heavy load.
> (10 base T 80 -90%). I checked and Mythbackend says 'changing from
> recordingonly to none.

I'm pretty sure this is mythcommflag thread flagging the commercials in your 
newly recorded show.  If the shows were local (on your HD) you'd see lots of 
disk activity after the show ends, but since you mount your recordings via 
NFS over the network you see lots of disk activity on your BSD machine and 
lots of network traffic to your Myth Box.  You could turn off commercial 
flagging if this bothers you.

>
> BTW Recorded file is fine!
>
> This heavy network activity stops when I close Mythbackend.
> Then everything is back to normal.
>
> I used Ethereal to do some sniffing, and this is wat it sees:
> 192.168.2.104 = MythMachine
> 192.168.2.111 = BSD server
>
> First during NORMAL recordings.
>
> 0.007241 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=1480)
> 0.007243 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=2960)
> 0.007244 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=4440)
> 0.007246 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=5920)
> 0.007247 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=7400)
> 0.010877 192.168.2.111 -> 192.168.2.104 UDP Source port: nfs
> Destination port: 800
> 0.019366 192.168.2.111 -> 192.168.2.104 NFS V3 WRITE Reply (Call In 4)
> Len:8192 UNSTABLE
> 0.024929 192.168.2.111 -> 192.168.2.104 NFS V3 WRITE Reply (Call In 11)
> Len:8192 UNSTABLE
> 0.031791 192.168.2.104 -> 192.168.2.111 NFS V3 WRITE Call, FH:0x0589ad16
> Offset:551989248 Len:8192 UNSTABLE[Unreassembled
> Packet]
> 0.031798 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=1480)
> 0.031799 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=2960)
> 0.031802 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=4440)
> 0.031805 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=5920)
> 0.031807 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=7400)
> 0.031879 192.168.2.104 -> 192.168.2.111 NFS V3 WRITE Call, FH:0x0589ad16
> Offset:551997440 Len:8192 UNSTABLE[Unreassembled
> Packet]
> 0.031881 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=1480)
> 0.031883 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=2960)
> 0.031886 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=4440)
> 0.031888 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=5920)
> 0.031891 192.168.2.104 -> 192.168.2.111 IP Fragmented IP protocol
> (proto=UDP 0x11, off=7400)
> 0.041478 192.168.2.111 -> 192.168.2.104 NFS V3 WRITE Reply (Call In 20)
> Len:8192 UNSTABLE
> 0.046993 192.168.2.111 -> 192.168.2.104 NFS V3 WRITE Reply (Call In 26)
> Len:8192 UNSTABLE
>
> And then AFTER recording has finished:
>
> 116.897668 192.168.2.104 -> 192.168.2.111 NFS V3 READ Call,
> FH:0x0589ad16 Offset:34922496 Len:8192
> 116.898309 192.168.2.111 -> 192.168.2.104 IP Fragmented IP protocol
> (proto=UDP 0x11, off=5920)
> 116.899094 192.168.2.111 -> 192.168.2.104 IP Fragmented IP protocol
> (proto=UDP 0x11, off=7400)
> 116.900325 192.168.2.111 -> 192.168.2.104 NFS V3 READ Reply (Call In
> 72487) Len:8192[Unreassembled Packet]
> 116.901556 192.168.2.111 -> 192.168.2.104 IP Fragmented IP protocol
> (proto=UDP 0x11, off=1480)
> 116.902789 192.168.2.111 -> 192.168.2.104 IP Fragmented IP protocol
> (proto=UDP 0x11, off=2960)
> 116.903331 192.168.2.104 -> 192.168.2.111 NFS V3 READ Call,
> FH:0x0589ad16 Offset:34930688 Len:8192
> 116.904020 192.168.2.111 -> 192.168.2.104 IP Fragmented IP protocol
> (proto=UDP 0x11, off=4440)
> 116.905253 192.168.2.111 -> 192.168.2.104 IP Fragmented IP protocol
> (proto=UDP 0x11, off=5920)
> 116.906041 192.168.2.111 -> 192.168.2.104 IP Fragmented IP protocol
> (proto=UDP 0x11, off=7400)
> 116.906223 192.168.2.104 -> 192.168.2.111 NFS V3 READ Call,
> FH:0x0589ad16 Offset:34938880 Len:8192
>
> This doesn't stop :-(
>
> It gets even stranger:
> When I decide to stop an ongoing recording by hand, there is no problem.
> Networkactivity stops.
>
> Does anyone know this problem?
> It seems Myth related because copying a file works fine?
> Maybe there's a sort of a work around, restart the backend if a
> recording finished?
>
> TIA Jack