[mythtv-users] mythtv + nfs = bad?

[Dale Pontius]

Alex Pearson wrote:
> mythtv-users-bounces at mythtv.org wrote on 09/05/2009 19:56:46:
> 
>> From:
>>
>> David Brodbeck <gull at gull.us>
>>
>> To:
>>
>> Discussion about mythtv <mythtv-users at mythtv.org>
>>
>> Date:
>>
>> 09/05/2009 19:15
>>
>> Subject:
>>
>> Re: [mythtv-users] mythtv + nfs = bad?
>>
>> Sent by:
>>
>> mythtv-users-bounces at mythtv.org
>>
>> Alex Pearson wrote:
>>> Hi All,
>>>         I'm not sure if this will help anyone, but I found nfs 
> unstable 
>>> on my box at home (which runs a number of nfs root'd servers as well 
> as 
>>> mythtv storage), I resolved the issue by setting the clients to tcp 
> and 
>>> also increasing the block size.  I now use the following mount 
> options:
>>>                 defaults,tcp,rsize=8192,wsize=8192 for general 
> servers.
>>>                 defaults,tcp,rsize=8192,wsize=8192,actimeo=0 for 
> mythtv.
>> If you're running nfsv3, I think 8192 may actually be *smaller* than the 
> 
>> default block size.  So you may have reduced it, not increased it.
>>
> 
> Its interesting you say that, I didn't spend a lot of time looking into 
> the block sizes (just dug in and had a play with them), but from the man 
> page:
> 
>                       "If an rsize value is not specified, or if the 
> specified rsize value is larger than the maximum that either  client  or 
> server can support, the client and server negotiate the largest rsize 
> value that they can both support."
> 
> 
> So you may well have a point!  Now I don't know whether I increased, or 
> decreased, the block size!  Oh well... If its not broke (which it isn't 
> now)
> 
>> I'm not going to argue with it if it fixed your problem, but I now tend 
>> to stay away from rsize and wsize tweaks.  They were necessary for older 
> 
>> NFS versions, but people have kept doing them as a sort of cargo cult 
>> ritual even on newer versions.
> 
> I guess I'm a member of the cult ;-)  Cool, never been in a cult 
> before....
> 
I'm running with:
nfs4	rw,hard,intr,rsize=32768,wsize=32768,nosuid,nodev
So the sizes can be bigger than 8192, and I guess I'm a member of the 
cult, too.  Smaller cult even, because I'm running nfs4.

Prodded by this thread, I'm experimenting with rebuilding the kernel on 
my backup server.  I tried applying the patch stuff, without luck.  The 
patch won't apply directly, I suspect because the web page I downloaded 
from did some whitespace damage.  I tried making the changes manually 
and messed something up.  So I'm working on the theory that there is 
some sort of fix in 2.6.29, and have copied svcsock.c and svc_xprt.c 
from a client machine.  I've had to backtrack some changes out of 
"svc_check_conn_limits", but finally have a clean compilation. Won't 
know if it works until I make_modules_install, reboot and try using nfs 
off of that machine, but at least I just got this far.

More to come...

Dale