[mythtv-users] nfs related frontend issues

Rich West Rich.West at wesmo.com
Wed Mar 21 01:54:39 UTC 2007

Ian Forde wrote:
> On Tue, 2007-03-20 at 18:14 -0400, Rich West wrote:
>> R. G. Newbury wrote:
>>> Blammo wrote:
>>>> On 3/20/07, John Goulah <jgoulah at gmail.com> wrote:
>>>>> Hi,
>>>>>  I had recently switched all of my data partitions to an NFS mounted
>>>>> filesystem.  Everything works fine, until the system is sitting for about a
>>>>> day or so, and then when I try to go into the videos they are gone, and I
>>>>> have to restart the frontend.  A similar problem happens with the music
>>>>> portion, except it just freezes when I click it.  Again restarting the
>>>>> frontend solves the problem. The NFS partitions stay mounted (I dont have to
>>>>> remount anything).  Is there anything I can do to resolve this, or ideas on
>>>>> where to look for the problem?
>>>> You might check your firewall setup on both backend and frontend. I
>>>> had an issue on a system I set up a few months ago, where iptables
>>>> kept killing NFS sessions after a "idle timeout".
>>>> You don't say what OS you're running, but if you're running a
>>>> redhat-derivitive (centos, rhel, fedora etc) you should be able to
>>>> stop the iptables service (as root) by typing "service iptables stop".
>>>> Give it 24 hours and see if that helps.
>>>> To stop the service from starting on boot (again on a redhat) you can
>>>> type "chkconfig iptables off"
>>> Better yet, if you are running Fedora (or RedHat derived) run the 
>>> program 'lokkit' and select the box to allow NFS. Lokkit is a small 
>>> program to configure the firewall/iptables in Fedora.
>>> If you find that you cannot mount your NFS share, and get a 'permission 
>>> denied' error, but that you can *then* get in, if you run 'iptables -F' 
>>> on the NFS server end of the pair, then your firewall is set to refuse 
>>> NFS access. Use lokkit.
>>> You should NOT just turn of iptables: That IS your firewall!
>> Off Topic, but if you are within your own internal (aka private) network 
>> with a firewall between your network and the rest of the internet, there 
>> is no need for individual firewalls on individual machines.
> Actually, that's an individual choice, and a good basic security
> practice...

Now we're way off topic.  Let's try to keep within the realm of mythtv 
rather than providing advice on non-myth related components.

I haven't seen any further responses from the original poster, so I can 
only hope that they managed to work out the issue.  There isn't much 
involved with an NFS setup:
o server (/etc/exports and the right rpc & nfs daemons running)
o client (/etc/fstab and the right rpc & nfs client daemons running)
If the original poster were using autofs (automounter), then that could 
have an impact as well.

Personally, I'm NFS mounting my videos and music volumes on my FE's from 
my main server (not my mythtv BE, but another machine) via autofs 
(backed by LDAP) and I haven't run in to the issue that was listed.

Responders to the original posting suggested disabling iptables (aka: 
the firewall), but did not add what appears to be the necessary 
disclaimer which would state that disabling iptables would be used as a 
method for _debugging_ the situation.  Since that disclaimer was implied 
rather than stated, those messages were followed by a couple of panicky 
responses and ended up causing an off-topic tangent.

So, in essence: disable the firewall, see if it makes a difference.  If 
it doesn't, then it isn't related to the firewall in any way, and you 
can choose to either re-enable it or leave it disabled (it is up to 
you).  If it does make a difference, then the problem is with your 
firewall and you will have to debug that further.

In either case, though, it is an OS level situation, not a MythTV one.


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