[mythtv-users] mythbackend crash - ALMOST SOLVED

[Robin Gilks]

> Greetings
>
> Another problem :-((
>
> This one is a bit more interesting. I'm running a diskless Epia system
> with all the filesystems NFS mounted on a server. I've just twigged that
> the backend on the Epia system crashes when the file it is recorded gets
> to 2048M. I'd seen this before but not associated it with anything in
> particular as I had not at that time "stabilised" my system.
>
> I assume its something to do with the way I have NFS set up - I'm not
> running quotas - but I can't see what values to tweak and where to remove
> this limit.
>
> Samba had a well known limit of 2G a couple of versions back but I can't
> see that that has any bearing at all on NFS!! ulimit doesn't have a factor
> for file size and any googling I do for an answer assumes I'm running
> quota.
>
> Hmmm - stumped :-(
>
I've nailed it down to the NFS mounts defaulting to version 2 which has
the  2G limit due to a cockup in my kernel config.

However, thats made me think that I should have something other than the
defaults in the client fstab - any suggestions for tuning NFS for large
video files?

I'm running Gentoo at both ends and I'm getting the error "nfs warning:
mount version older than kernel" but its running version 3 OK according to
/proc/mounts so what is the version difference its complaining about?

A few system details... 1st the server
zeus ~ # cat /proc/mounts
rootfs / rootfs rw 0 0
/dev/root / ext3 rw,noatime 0 0
proc /proc proc rw,nodiratime 0 0
sysfs /sys sysfs rw 0 0
devfs /dev devfs rw 0 0
devpts /dev/pts devpts rw 0 0
none /dev/shm tmpfs rw 0 0
/dev/vg/backup /mnt/backup ext3 rw,noatime 0 0
/dev/vg/games /mnt/games ext3 rw,noatime 0 0
/dev/vg/music /mnt/music ext3 rw,noatime 0 0
/dev/vg/pictures /mnt/pictures ext3 rw,noatime 0 0
/dev/vg/store /mnt/store ext3 rw,noatime 0 0
/dev/vg/videos /mnt/videos ext3 rw,noatime 0 0
/dev/vg/g8ecj-storage /home/g8ecj/storage ext3 rw,noatime 0 0
/dev/vg/steph-storage /home/steph/storage ext3 rw,noatime 0 0
/dev/vg/www /var/www ext3 rw,noatime 0 0
/dev/vg/tmp /tmp ext3 rw,noatime 0 0
usbfs /proc/bus/usb usbfs rw 0 0
nfsd /proc/fs/nfs nfsd rw 0 0
/dev/md0 /boot ext2 rw,noatime 0 0
zeus ~ # emerge -pv nfs-utils

These are the packages that I would merge, in order:

Calculating dependencies ...done!
[ebuild   R   ] net-fs/nfs-utils-1.0.6-r6  +tcpd 0 kB

Next, the diskless client
media ~ # uname -a
Linux media 2.6.12-gentoo-r9 #3 Wed Oct 19 22:27:30 NZDT 2005 i686 VIA
Nehemiah CentaurHauls GNU/Linux
media ~ # cat /proc/mounts
rootfs / rootfs rw 0 0
/dev/root / nfs
rw,noatime,v2,rsize=4096,wsize=4096,hard,udp,nolock,addr=192.168.1.15 0 0
proc /proc proc rw,nodiratime 0 0
sysfs /sys sysfs rw 0 0
udev /dev tmpfs rw,nosuid 0 0
devpts /dev/pts devpts rw 0 0
none /dev/shm tmpfs rw 0 0
usbfs /proc/bus/usb usbfs rw 0 0
zeus:/mnt/videos /mnt/videos nfs
rw,v3,rsize=32768,wsize=32768,hard,udp,lock,addr=zeus 0 0
zeus:/mnt/music /mnt/music nfs
rw,v3,rsize=32768,wsize=32768,hard,udp,lock,addr=zeus 0 0
zeus:/mnt/store /mnt/store nfs
rw,v3,rsize=32768,wsize=32768,hard,udp,lock,addr=zeus 0 0
zeus:/mnt/games /mnt/games nfs
rw,v3,rsize=32768,wsize=32768,hard,udp,lock,addr=zeus 0 0
zeus:/mnt/pictures /mnt/pictures nfs
rw,v3,rsize=32768,wsize=32768,hard,udp,lock,addr=zeus 0 0

Hope that provides some useful data.

-- 
Robin Gilks