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nfs pauses

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yiannividalis at hotmail

Nov 10, 2009, 10:18 AM

Post #1 of 19 (1607 views)
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nfs pauses

Hi.

I am facing a strange problem lately and I hope someone here can provide some insight (or a solution....).

Most of my videos are stored in an nfs share. The share is mounted in fstab using rw,rsize=32768,wsize=32768,bg. While watching them on my frontend, there are occasionally pauses, as if the file "is not there" when the frontend needs it. I notice it especially with films with AC3 sound because the "AC3" led on the amplifier is turned off momentarily. The nfs share is on an opensuse 11.1 pc, stored on raid 5 on top of lvm (talking about redundancy....). The strange thing is that I didn't always have this problem, it must have happened after one of the latest package upgrades, so I suspect something to do with the latest opensuse kernel (2.6.27.37-0.1 x86_64). The ethernet card is an onboard gigabit, using the r8169 module. The frontend card is 100mbps (8139too module).

I am running mythtv trunk, version 22772. I thought it might have been VDPAU, but disabling it made no difference. I am using Graphite, so turning off "Extra audio buffering" would not make any difference. I also tried with actimeo=0 and 5 and with the option completely removed. Same behaviour.

Using the system monitor on the nfs server, I noticed that that network throughoutput is non constant, but the videos are served in "peaks" around 20 secs apart. The pauses occur during these peaks, which are shorter and wider when a pause occurs.

Watching part of a suspect video with xine was smooth, although I admit I watched only 5-6 minutes of it. Moving the file locally and watching it in mythtv shows no problems, either.

I have no other network problems between the two pcs, the ssh connections are never broken even after hours of idle time, file transfers are smooth and fast for 100mbps network. Is it true to suspect that some latency has increased, either on the filesystem or the network driver? Has anyone faced any similar problems? Can you please suggest a possible solution?

Thank you for a very great program, I am very happy that 0.22 is out, although I will continue to run trunk because now I'm ... addicted to it.

Thank you,

Yianni.

_________________________________________________________________
Windows Live: Κρατήστε τους φίλους σας ενήμερους για τις δραστηριότητές σας στο Internet.
http://www.microsoft.com/windows/windowslive/see-it-in-action/social-network-basics.aspx?ocid=PID23461::T:WLMTAGL:ON:WL:el-gr:SI_SB_1:092009

yiannividalis at hotmail

Nov 10, 2009, 11:15 AM

Post #2 of 19 (1571 views)
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Re: nfs pauses [In reply to]

From: yiannividalis [at] hotmail
To: mythtv-users [at] mythtv
Date: Tue, 10 Nov 2009 20:18:57 +0200
Subject: [mythtv-users] nfs pauses

Hi.

I am facing a strange problem lately and I hope someone here can provide some insight (or a solution....).

Most of my videos are stored in an nfs share. The share is mounted in fstab using rw,rsize=32768,wsize=32768,bg. While watching them on my frontend, there are occasionally pauses, as if the file "is not there" when the frontend needs it. I notice it especially with films with AC3 sound because the "AC3" led on the amplifier is turned off momentarily. The nfs share is on an opensuse 11.1 pc, stored on raid 5 on top of lvm (talking about redundancy....). The strange thing is that I didn't always have this problem, it must have happened after one of the latest package upgrades, so I suspect something to do with the latest opensuse kernel (2.6.27.37-0.1 x86_64). The ethernet card is an onboard gigabit, using the r8169 module. The frontend card is 100mbps (8139too module).

I am running mythtv trunk, version 22772. I thought it might have been VDPAU, but disabling it made no difference. I am using Graphite, so turning off "Extra audio buffering" would not make any difference. I also tried with actimeo=0 and 5 and with the option completely removed. Same behaviour.
Using the system monitor on the nfs server, I noticed that that network throughoutput is non constant, but the videos are served in "peaks" around 20 secs apart. The pauses occur during these peaks, which are shorter and wider when a pause occurs.

Watching part of a suspect video with xine was smooth, although I admit I watched only 5-6 minutes of it. Moving the file locally and watching it in mythtv shows no problems, either.

I have no other network problems between the two pcs, the ssh connections are never broken even after hours of idle time, file transfers are smooth and fast for 100mbps network. Is it true to suspect that some latency has increased, either on the filesystem or the network driver? Has anyone faced any similar problems? Can you please suggest a possible solution?

Thank you for a very great program, I am very happy that 0.22 is out, although I will continue to run trunk because now I'm ... addicted to it.

Thank you,

Yianni.

------------------

Following this up, I noticed that using xine, the program doesn't pause because it fetches data constantly. The network diagram is more like continuous waves than completely separate peaks, so the file is never "forgotten" by the filesystem / network (I again assume that this is that is causing it). Is there any way I can persuade mythtv to behave similarly or is this option (if it exists) hidden deeply in code that shouldn't be touched? (My C++ skills are zero, but I can change some line if you point me to it).

Thanks again,

Yianni.
_________________________________________________________________
Νέα Windows 7: Βρείτε τον κατάλληλο υπολογιστή για εσάς. Μάθετε περισσότερα.
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yiannividalis at hotmail

Nov 10, 2009, 11:44 AM

Post #3 of 19 (1574 views)
Permalink

Re: nfs pauses [In reply to]

________________________________
> From: yiannividalis [at] hotmail
> To: mythtv-users [at] mythtv
> Date: Tue, 10 Nov 2009 20:18:57 +0200
> Subject: [mythtv-users] nfs pauses
>
>
>
>
>
>
>
>
> Hi.
>
>
>
> I am facing a strange problem lately and I hope someone here can provide some insight (or a solution....).
>
>
>
> Most of my videos are stored in an nfs share. The share is mounted in fstab using rw,rsize=32768,wsize=32768,bg. While watching them on my frontend, there are occasionally pauses, as if the file "is not there" when the frontend needs it. I notice it especially with films with AC3 sound because the "AC3" led on the amplifier is turned off momentarily. The nfs share is on an opensuse 11.1 pc, stored on raid 5 on top of lvm (talking about redundancy....). The strange thing is that I didn't always have this problem, it must have happened after one of the latest package upgrades, so I suspect something to do with the latest opensuse kernel (2.6.27.37-0.1 x86_64). The ethernet card is an onboard gigabit, using the r8169 module. The frontend card is 100mbps (8139too module).
>
>
>
> I am running mythtv trunk, version 22772. I thought it might have been VDPAU, but disabling it made no difference. I am using Graphite, so turning off "Extra audio buffering" would not make any difference. I also tried with actimeo=0 and 5 and with the option completely removed. Same behaviour.
>
> Using the system monitor on the nfs server, I noticed that that network throughoutput is non constant, but the videos are served in "peaks" around 20 secs apart. The pauses occur during these peaks, which are shorter and wider when a pause occurs.
>
>
>
> Watching part of a suspect video with xine was smooth, although I admit I watched only 5-6 minutes of it. Moving the file locally and watching it in mythtv shows no problems, either.
>
>
>
> I have no other network problems between the two pcs, the ssh connections are never broken even after hours of idle time, file transfers are smooth and fast for 100mbps network. Is it true to suspect that some latency has increased, either on the filesystem or the network driver? Has anyone faced any similar problems? Can you please suggest a possible solution?
>
>
>
> Thank you for a very great program, I am very happy that 0.22 is out, although I will continue to run trunk because now I'm ... addicted to it.
>
>
>
> Thank you,
>
>
>
> Yianni.
>
> ________________________________

Following this up, I noticed that using xine, the program doesn't pause because it fetches data constantly. The network diagram is more like continuous waves than completely separate peaks, so the file is never "forgotten" by the filesystem / network (I again assume that this is that is causing it). Is there any way I can persuade mythtv to behave similarly or is this option (if it exists) hidden deeply in code that shouldn't be touched? (My C++ skills are zero, but I can change some line if you point me to it).

Thanks again,

Yianni.

_________________________________________________________________
Το What's New σας ειδοποιεί άμεσα για κάθε ενημέρωση. Μάθετε πώς.
http://home.live.com/
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

yiannividalis at hotmail

Nov 10, 2009, 11:53 AM

Post #4 of 19 (1573 views)
Permalink

Re: nfs pauses [In reply to]

________________________________
> From: yiannividalis [at] hotmail
> To: mythtv-users [at] mythtv
> Subject: nfs pauses
> Date: Tue, 10 Nov 2009 20:18:57 +0200
>
>
>
>
>
>
>
>
> Hi.
>
>
>
> I am facing a strange problem lately and I hope someone here can provide some insight (or a solution....).
>
>
>
> Most of my videos are stored in an nfs share. The share is mounted in fstab using rw,rsize=32768,wsize=32768,bg. While watching them on my frontend, there are occasionally pauses, as if the file "is not there" when the frontend needs it. I notice it especially with films with AC3 sound because the "AC3" led on the amplifier is turned off momentarily. The nfs share is on an opensuse 11.1 pc, stored on raid 5 on top of lvm (talking about redundancy....). The strange thing is that I didn't always have this problem, it must have happened after one of the latest package upgrades, so I suspect something to do with the latest opensuse kernel (2.6.27.37-0.1 x86_64). The ethernet card is an onboard gigabit, using the r8169 module. The frontend card is 100mbps (8139too module).
>
>
>
> I am running mythtv trunk, version 22772. I thought it might have been VDPAU, but disabling it made no difference. I am using Graphite, so turning off "Extra audio buffering" would not make any difference. I also tried with actimeo=0 and 5 and with the option completely removed. Same behaviour.
>
> Using the system monitor on the nfs server, I noticed that that network throughoutput is non constant, but the videos are served in "peaks" around 20 secs apart. The pauses occur during these peaks, which are shorter and wider when a pause occurs.
>
>
>
> Watching part of a suspect video with xine was smooth, although I admit I watched only 5-6 minutes of it. Moving the file locally and watching it in mythtv shows no problems, either.
>
>
>
> I have no other network problems between the two pcs, the ssh connections are never broken even after hours of idle time, file transfers are smooth and fast for 100mbps network. Is it true to suspect that some latency has increased, either on the filesystem or the network driver? Has anyone faced any similar problems? Can you please suggest a possible solution?
>
>
>
> Thank you for a very great program, I am very happy that 0.22 is out, although I will continue to run trunk because now I'm ... addicted to it.
>
>
>
> Thank you,
>
>
>
> Yianni.
>
> ________________________________

Following this up, I noticed that when I am using xine, the program doesn't pause because it fetches data constantly. The network diagram looks more like continuous low waves than completely separate peaks, so the file is never "forgotten" by the filesystem / network (I again assume that this is that is causing it).

Is there any way I can persuade mythtv to behave similarly or is this option (if it exists) hidden deeply in code that shouldn't be touched? (My C++ skills are zero, but I can change some line if you point me to it).

Thanks again,

Yianni.
_________________________________________________________________
Windows Live: Κρατήστε τους φίλους σας ενήμερους για τις δραστηριότητές σας στο Internet.
http://www.microsoft.com/windows/windowslive/see-it-in-action/social-network-basics.aspx?ocid=PID23461::T:WLMTAGL:ON:WL:el-gr:SI_SB_1:092009
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

yiannividalis at hotmail

Nov 10, 2009, 12:07 PM

Post #5 of 19 (1561 views)
Permalink

Re: nfs pauses [In reply to]

From: yiannividalis [at] hotmail
To: mythtv-users [at] mythtv
Date: Tue, 10 Nov 2009 20:18:57 +0200
Subject: [mythtv-users] nfs pauses

Hi.

I am facing a strange problem lately and I hope someone here can provide some insight (or a solution....).

Most of my videos are stored in an nfs share. The share is mounted in fstab using rw,rsize=32768,wsize=32768,bg. While watching them on my frontend, there are occasionally pauses, as if the file "is not there" when the frontend needs it. I notice it especially with films with AC3 sound because the "AC3" led on the amplifier is turned off momentarily. The nfs share is on an opensuse 11.1 pc, stored on raid 5 on top of lvm (talking about redundancy....). The strange thing is that I didn't always have this problem, it must have happened after one of the latest package upgrades, so I suspect something to do with the latest opensuse kernel (2.6.27.37-0.1 x86_64). The ethernet card is an onboard gigabit, using the r8169 module. The frontend card is 100mbps (8139too module).

I am running mythtv trunk, version 22772. I thought it might have been VDPAU, but disabling it made no difference. I am using Graphite, so turning off "Extra audio buffering" would not make any difference. I also tried with actimeo=0 and 5 and with the option completely removed. Same behaviour.
Using the system monitor on the nfs server, I noticed that that network throughoutput is non constant, but the videos are served in "peaks" around 20 secs apart. The pauses occur during these peaks, which are shorter and wider when a pause occurs.

Watching part of a suspect video with xine was smooth, although I admit I watched only 5-6 minutes of it. Moving the file locally and watching it in mythtv shows no problems, either.

I have no other network problems between the two pcs, the ssh connections are never broken even after hours of idle time, file transfers are smooth and fast for 100mbps network. Is it true to suspect that some latency has increased, either on the filesystem or the network driver? Has anyone faced any similar problems? Can you please suggest a possible solution?

Thank you for a very great program, I am very happy that 0.22 is out, although I will continue to run trunk because now I'm ... addicted to it.

Thank you,

Yianni.

Following this up, I noticed that using xine, the program doesn't pause because it fetches data constantly. The network diagram is more like continuous waves than completely separate peaks, so the file is never "forgotten" by the filesystem / network (I again assume that this is that is causing it). Is there any way I can persuade mythtv to behave similarly or is this option (if it exists) hidden deeply in code that shouldn't be touched? (My C++ skills are zero, but I can change some line if you point me to it).

Thanks again,

Yianni.

_________________________________________________________________
Το What's New σας ειδοποιεί άμεσα για κάθε ενημέρωση. Μάθετε πώς.
http://home.live.com/

torbjorn.jansson at gmail

Nov 10, 2009, 1:36 PM

Post #6 of 19 (1573 views)
Permalink

Re: nfs pauses [In reply to]

2009/11/10 Yianni Vidalis <yiannividalis [at] hotmail>:
> Hi.
>
> I am facing a strange problem lately and I hope someone here can provide
> some insight (or a solution....).
>

you didn't say what type of computer you were using, but try ssh:ing
in to your frontend box from another computer and start iptraf and go
to detailed interface stats and select your ethernet interface.
leave it running and then test your playback.

i know it sounds weird but this "trick" makes my epia m10k frontend
work just fine with fedora 11, no periodic pausing as long as iptraf
is running with interface stats counting.
this problem didn't always exist and i am pretty sure its kernel related.
i saw a post and patch about something with the via drm thingy that
was broken somehow and it was supposed to be fixed in 2.6.31 kernel.

older kernels have worked fine so its a problem that have shown up in
the latest few kernel versions.

(resending because last mail bounced with some error about the mail
man dying with signal 9 or something)
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DEPontius at edgehp

Nov 10, 2009, 3:22 PM

Post #7 of 19 (1573 views)
Permalink

Re: nfs pauses [In reply to]

Yianni Vidalis wrote:
> Hi.
>
> I am facing a strange problem lately and I hope someone here can provide
> some insight (or a solution....).
>
> Most of my videos are stored in an nfs share. The share is mounted in
> fstab using rw,rsize=32768,wsize=32768,bg. While watching them on my
> frontend, there are occasionally pauses, as if the file "is not there"
> when the frontend needs it. I notice it especially with films with AC3
> sound because the "AC3" led on the amplifier is turned off momentarily.
> The nfs share is on an opensuse 11.1 pc, stored on raid 5 on top of lvm
> (talking about redundancy....). The strange thing is that I didn't
> always have this problem, it must have happened after one of the latest
> package upgrades, so I suspect something to do with the latest opensuse
> kernel (2.6.27.37-0.1 x86_64). The ethernet card is an onboard gigabit,
> using the r8169 module. The frontend card is 100mbps (8139too module).
>
> I am running mythtv trunk, version 22772. I thought it might have been
> VDPAU, but disabling it made no difference. I am using Graphite, so
> turning off "Extra audio buffering" would not make any difference. I
> also tried with actimeo=0 and 5 and with the option completely removed.
> Same behaviour.
> Using the system monitor on the nfs server, I noticed that that network
> throughoutput is non constant, but the videos are served in "peaks"
> around 20 secs apart. The pauses occur during these peaks, which are
> shorter and wider when a pause occurs.
>
> Watching part of a suspect video with xine was smooth, although I admit
> I watched only 5-6 minutes of it. Moving the file locally and watching
> it in mythtv shows no problems, either.
>
> I have no other network problems between the two pcs, the ssh
> connections are never broken even after hours of idle time, file
> transfers are smooth and fast for 100mbps network. Is it true to suspect
> that some latency has increased, either on the filesystem or the network
> driver? Has anyone faced any similar problems? Can you please suggest a
> possible solution?
>
> Thank you for a very great program, I am very happy that 0.22 is out,
> although I will continue to run trunk because now I'm ... addicted to it.
>
> Thank you,
>
> Yianni.

There are 2 possibilities I can suggest.

First, there were some NFS problems in the kernel, starting around
2.6.25/26 and finally getting fixed at 2.6.29. If you're comfortable,
you might want to manually upgrade your kernel. 2.6.29 is reasonably
compatible with 2.6.25/26 - it's 2.6.30 where things started moving kind
of fast and required significant configuration tweaking.

Second, are you by chance also running your $HOME directories on the
same NFS server? When Firefox moved to sqlite for storing its stuff, it
became rather infamous for filesystem stress - and that's stressing
local filesystems. I was running this way, and it was bringing my NFS
server to its knees periodically. I've since symlinked $HOME/.mozilla
back onto a local filesystem and things have gotten better. None of
this was helped by the fact that my servers are ancient flea-market or
hamfest junk, and perhaps easily overwhelmed by a modern system.

Dale
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nick.rout at gmail

Nov 10, 2009, 4:00 PM

Post #8 of 19 (1565 views)
Permalink

Re: nfs pauses [In reply to]

2009/11/11 Yianni Vidalis <yiannividalis [at] hotmail>:
>

>
> I am facing a strange problem lately and I hope someone here can provide some insight (or a solution....).
>
> Most of my videos are stored in an nfs share. The share is mounted in fstab using rw,rsize=32768,wsize=32768,bg. While watching them on my frontend, there are occasionally pauses, as if the file "is not there" when the frontend needs it. I notice it especially with films with AC3 sound because the "AC3" led on the amplifier is turned off momentarily. The nfs share is on an opensuse 11.1 pc, stored on raid 5 on top of lvm (talking about redundancy....). The strange thing is that I didn't always have this problem, it must have happened after one of the latest package upgrades, so I suspect something to do with the latest opensuse kernel (2.6.27.37-0.1 x86_64). The ethernet card is an onboard gigabit, using the r8169 module. The frontend card is 100mbps (8139too module).
>
> I am running mythtv trunk, version 22772. I thought it might have been VDPAU, but disabling it made no difference. I am using Graphite, so turning off "Extra audio buffering" would not make any difference. I also tried with actimeo=0 and 5 and with the option completely removed. Same behaviour.
> Using the system monitor on the nfs server, I noticed that that network throughoutput is non constant, but the videos are served in "peaks" around 20 secs apart. The pauses occur during these peaks, which are shorter and wider when a pause occurs.
>
> Watching part of a suspect video with xine was smooth, although I admit I watched only 5-6 minutes of it. Moving the file locally and watching it in mythtv shows no problems, either.
>
> I have no other network problems between the two pcs, the ssh connections are never broken even after hours of idle time, file transfers are smooth and fast for 100mbps network. Is it true to suspect that some latency has increased, either on the filesystem or the network driver? Has anyone faced any similar problems? Can you please suggest a possible solution?
>
> Thank you for a very great program, I am very happy that 0.22 is out, although I will continue to run trunk because now I'm ... addicted to it.
>
> Thank you,
>
> Yianni.
>
>
> ------------------
>
>
> Following this up, I noticed that using xine, the program doesn't pause because it fetches data constantly. The network diagram is more like continuous waves than completely separate peaks, so the file is never "forgotten" by the filesystem / network (I again assume that this is that is causing it). Is there any way I can persuade mythtv to behave similarly or is this option (if it exists) hidden deeply in code that shouldn't be touched? (My C++ skills are zero, but I can change some line if you point me to it).
>

I have heard people say that they have better results with sshfs or
cifs than nfs, may be worth a try.
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mail at benlancaster

Nov 11, 2009, 6:14 AM

Post #9 of 19 (1556 views)
Permalink

Re: nfs pauses [In reply to]

> Most of my videos are stored in an nfs share. The share is mounted
> in fstab using rw,rsize=32768,wsize=32768,bg. While watching them on
> my frontend, there are occasionally pauses, as if the file "is not
> there" when the frontend needs it.

Personally, I'd lose the rsize, wsize from your fstab - they're
unnecessarily huge IMHO, maybe lose 'bg' too and replace it with
'hard' as this'll show up any nfs server errors in the clients' /var/
log/messages.

I had similar symptoms to you on MythBuntu (with and without
problematic kernel), and leaving it with the Ubuntu defaults (replace
your options with "defaults") solved all my problems. I also get
consistently faster transfer rates now too.

Might be worth checking that your link speed is as fast as it'll go
with ifconfig or ethtool too.

1p.

Ben
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myth at robinhill

Nov 11, 2009, 7:41 AM

Post #10 of 19 (1538 views)
Permalink

Re: nfs pauses [In reply to]

On Wed Nov 11, 2009 at 02:14:34PM +0000, Ben Lancaster wrote:

> > Most of my videos are stored in an nfs share. The share is mounted
> > in fstab using rw,rsize=32768,wsize=32768,bg. While watching them on
> > my frontend, there are occasionally pauses, as if the file "is not
> > there" when the frontend needs it.
>
> Personally, I'd lose the rsize, wsize from your fstab - they're
> unnecessarily huge IMHO, maybe lose 'bg' too and replace it with
> 'hard' as this'll show up any nfs server errors in the clients' /var/
> log/messages.
>
The rsize & wsize are not particularly large, but should be removed
anyway as this will allow the client & server to negotiate the optimum
size (524288 on mine). The bg option will only make any difference when
mounting, so won't be impacting you here - it should probably be left in
to speed up booting though. I'd recommend specifying tcp in there too -
it's the default anyway, but it's best to be sure.

HTH,
Robin
--
___
( ' } | Robin Hill <myth [at] robinhill> |
/ / ) | Little Jim says .... |
// !! | "He fallen in de water !!" |

yiannividalis at hotmail

Nov 11, 2009, 12:52 PM

Post #11 of 19 (1522 views)
Permalink

Re: nfs pauses [In reply to]

First of all, thank you all for your input.

Sorry it took me so long to post but I've been very busy. And please accept my apologies for the unnecessarily repeated posts, but either hotmail or the List had a problem while I was trying to post the first time.

Anyway, what I tried so far with the nfs server (opensuse):

- I downgraded my opensuse 11.1 kernel to 2.6.27.29-0.1-default (I kept the .rpm) but the problem is still there. It is the kernel I am still running.

- I followed torbjorn.jansson at gmail 's suggestion about iptraf, but I had no success. Trying a similar approach, I tried pinging from the nfs server the frontend but no success, either. (by the way, my frontend is a debian Lenny system (2.6.26 kernel)).

- Reading myth at robinhill 's post I changed the fstab entry to rw,sync,hard. This is the best behaviour so far, meaning that the first pause occured 5 minutes into the video. I guess it's due to the increased {w,r}size.

- Trying mail at benlancaster's suggestion: Sorry, but using the defaults doesn't work for me. The pauses occur very often.

- I even tried to decrease {w,r}size to 4096 and later to 2048 bytes. Still problem.

So far I am using the rw,sync,hard mount option, because it is the one with the least pauses. I will install the latest kernel as before since it doesn't seem to affect anything, and I will probably wait for opensuse 11.2 to come out (it is on T-18 today) which has 2.6.31.5 kernel and other improvements. You see, I still think it's a nfs or kernel or network problem (can you imagine how I'll feel if I see a relevant commit in myth trunk? LOL)

Thank's again for your response,

Yianni.
_________________________________________________________________
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belcampo at zonnet

Nov 12, 2009, 6:13 AM

Post #12 of 19 (1517 views)
Permalink

Re: nfs pauses [In reply to]

Yianni Vidalis wrote:
> First of all, thank you all for your input.
>
> Sorry it took me so long to post but I've been very busy. And please accept my apologies for the unnecessarily repeated posts, but either hotmail or the List had a problem while I was trying to post the first time.
>
> Anyway, what I tried so far with the nfs server (opensuse):
>
> - I downgraded my opensuse 11.1 kernel to 2.6.27.29-0.1-default (I kept the .rpm) but the problem is still there. It is the kernel I am still running.
>
> - I followed torbjorn.jansson at gmail 's suggestion about iptraf, but I had no success. Trying a similar approach, I tried pinging from the nfs server the frontend but no success, either. (by the way, my frontend is a debian Lenny system (2.6.26 kernel)).
>
> - Reading myth at robinhill 's post I changed the fstab entry to rw,sync,hard. This is the best behaviour so far, meaning that the first pause occured 5 minutes into the video. I guess it's due to the increased {w,r}size.
>
> - Trying mail at benlancaster's suggestion: Sorry, but using the defaults doesn't work for me. The pauses occur very often.
>
> - I even tried to decrease {w,r}size to 4096 and later to 2048 bytes. Still problem.
>
> So far I am using the rw,sync,hard mount option, because it is the one with the least pauses. I will install the latest kernel as before since it doesn't seem to affect anything, and I will probably wait for opensuse 11.2 to come out (it is on T-18 today) which has 2.6.31.5 kernel and other improvements. You see, I still think it's a nfs or kernel or network problem (can you imagine how I'll feel if I see a relevant commit in myth trunk? LOL)
>
> Thank's again for your response,
>
> Yianni.
> _________________________________________________________________
> Έχετε Messenger; Έχετε και Windows Live. Μάθετε περισσότερα.
> http://microsoft.com/windows/windowslive
> _______________________________________________
> mythtv-users mailing list
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> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
2.6.27 kernels are 'known' to have nfs related problems
Default, if nothing is defined at server and client side, rsize and
wsize should be 1048576
If server side doesn't do this by default for whatever reason you can
force it in one of your boot-scripts with:

echo 1048576 > /proc/fs/nfsd/max_block_size

Your client will then negotiate what maximum is acceptable which also
should be 1048576.
Check with less /etc/proc/mounts
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yiannividalis at hotmail

Nov 12, 2009, 7:08 AM

Post #13 of 19 (1524 views)
Permalink

Re: nfs pauses [In reply to]

----------------------------------------
> Date: Thu, 12 Nov 2009 15:13:55 +0100
> From: belcampo [at] zonnet
> To: mythtv-users [at] mythtv
> Subject: Re: [mythtv-users] nfs pauses
>
> Yianni Vidalis wrote:
>> First of all, thank you all for your input.
>>
>> Sorry it took me so long to post but I've been very busy. And please accept my apologies for the unnecessarily repeated posts, but either hotmail or the List had a problem while I was trying to post the first time.
>>
>> Anyway, what I tried so far with the nfs server (opensuse):
>>
>> - I downgraded my opensuse 11.1 kernel to 2.6.27.29-0.1-default (I kept the .rpm) but the problem is still there. It is the kernel I am still running.
>>
>> - I followed torbjorn.jansson at gmail 's suggestion about iptraf, but I had no success. Trying a similar approach, I tried pinging from the nfs server the frontend but no success, either. (by the way, my frontend is a debian Lenny system (2.6.26 kernel)).
>>
>> - Reading myth at robinhill 's post I changed the fstab entry to rw,sync,hard. This is the best behaviour so far, meaning that the first pause occured 5 minutes into the video. I guess it's due to the increased {w,r}size.
>>
>> - Trying mail at benlancaster's suggestion: Sorry, but using the defaults doesn't work for me. The pauses occur very often.
>>
>> - I even tried to decrease {w,r}size to 4096 and later to 2048 bytes. Still problem.
>>
>> So far I am using the rw,sync,hard mount option, because it is the one with the least pauses. I will install the latest kernel as before since it doesn't seem to affect anything, and I will probably wait for opensuse 11.2 to come out (it is on T-18 today) which has 2.6.31.5 kernel and other improvements. You see, I still think it's a nfs or kernel or network problem (can you imagine how I'll feel if I see a relevant commit in myth trunk? LOL)
>>
>> Thank's again for your response,
>>
>> Yianni.
>> _________________________________________________________________
>> Έχετε Messenger; Έχετε και Windows Live. Μάθετε περισσότερα.
>> http://microsoft.com/windows/windowslive
>> _______________________________________________
>> mythtv-users mailing list
>> mythtv-users [at] mythtv
>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> 2.6.27 kernels are 'known' to have nfs related problems
> Default, if nothing is defined at server and client side, rsize and
> wsize should be 1048576
> If server side doesn't do this by default for whatever reason you can
> force it in one of your boot-scripts with:
>
> echo 1048576> /proc/fs/nfsd/max_block_size
>
>
> Your client will then negotiate what maximum is acceptable which also
> should be 1048576.
> Check with less /etc/proc/mounts
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

Thank you, you are correct, 1048576 is the current value. I didn't have to force it, the pcs negotiated it.

Apparently, opensuse 11.2 is out now and I will be very busy during the weekend (if I wait that long). If it's a kernel problem, this will solve it. If it isn't, well...
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gull at gull

Nov 12, 2009, 4:29 PM

Post #14 of 19 (1480 views)
Permalink

Re: nfs pauses [In reply to]

Sorry if you've already mentioned this...

Have you tried running "top" on the NFS server and watching the CPU load
while you play a video? Maybe something is consuming a lot of CPU during
the pauses.

Also, what's the network activity like during a pause? Does it stop, or
does it continue?

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yiannividalis at hotmail

Nov 13, 2009, 11:22 AM

Post #15 of 19 (1455 views)
Permalink

Re: nfs pauses [In reply to]

----------------------------------------
> Date: Thu, 12 Nov 2009 16:29:37 -0800
> From: gull [at] gull
> To: mythtv-users [at] mythtv
> Subject: Re: [mythtv-users] nfs pauses
>
> Sorry if you've already mentioned this...
>
> Have you tried running "top" on the NFS server and watching the CPU load
> while you play a video? Maybe something is consuming a lot of CPU during
> the pauses.
>
> Also, what's the network activity like during a pause? Does it stop, or
> does it continue?
>
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

There was no extra cpu activity during the pauses. Also, the network activity was flat when no pause was occuring (nothing else was moving from or to the nfs server). The pauses occur when mythtv fetches the next piece of the video (or when the nfs client does). You can see my description on my first post, if you'd like.

However, the nfs server is currently doing an inplace upgrade from opensuse 11.1 to 11.2. I hope everything works out ok, I couldn't resist trying the new (for opensuse, at least) upgrade method.

Yianni.
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gull at gull

Nov 13, 2009, 11:35 AM

Post #16 of 19 (1459 views)
Permalink

Re: nfs pauses [In reply to]

On Fri, November 13, 2009 11:22 am, Yianni Vidalis wrote:
> There was no extra cpu activity during the pauses. Also, the network
> activity was flat when no pause was occuring (nothing else was moving from
> or to the nfs server). The pauses occur when mythtv fetches the next piece
> of the video (or when the nfs client does). You can see my description on
> my first post, if you'd like.

OK, figured it was worth a shot.

Last time I had a problem like that it turned out to be a flaky network
card. Under heavy load it would drop a few packets, then NFS would sit
around waiting for RPC retries.

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mache at creeger

Nov 13, 2009, 5:20 PM

Post #17 of 19 (1436 views)
Permalink

Re: nfs pauses [In reply to]

What do you have under "General Playback (1/9)?

I have the following items checked.

Extra Audio Buffering
Clear saved position on playback
Alternate clear saved position
Jump to Program OSD
Always stream recordings from the backend
Enable picture controls

The checking of "Use video as a timebase", may cause this type of problem.

-- Mache

At 11:35 AM 11/13/2009, David Brodbeck wrote:
>On Fri, November 13, 2009 11:22 am, Yianni Vidalis wrote:
> > There was no extra cpu activity during the pauses. Also, the network
> > activity was flat when no pause was occuring (nothing else was moving from
> > or to the nfs server). The pauses occur when mythtv fetches the next piece
> > of the video (or when the nfs client does). You can see my description on
> > my first post, if you'd like.
>
>OK, figured it was worth a shot.
>
>Last time I had a problem like that it turned out to be a flaky network
>card. Under heavy load it would drop a few packets, then NFS would sit
>around waiting for RPC retries.

yiannividalis at hotmail

Nov 16, 2009, 8:16 AM

Post #18 of 19 (1346 views)
Permalink

Re: nfs pauses [In reply to]

________________________________
> Date: Fri, 13 Nov 2009 17:20:03 -0800
> To: mythtv-users [at] mythtv
> From: mache [at] creeger
> Subject: Re: [mythtv-users] nfs pauses
>
>
>
> What do you have under "General Playback
> (1/9)?
>
>
> I have the following items checked.
>
>
> Extra Audio Buffering
>
> Clear saved position on playback
>
> Alternate clear saved position
>
> Jump to Program OSD
>
> Always stream recordings from the backend
>
> Enable picture controls
>
>
> The checking of "Use video as a timebase", may cause this type
> of problem.
>
>
> -- Mache
>
>
> At 11:35 AM 11/13/2009, David Brodbeck wrote:
>
> On Fri, November 13, 2009 11:22
> am, Yianni Vidalis wrote:
>
>> There was no extra cpu activity during the pauses. Also, the
> network
>
>> activity was flat when no pause was occuring (nothing else was
> moving from
>
>> or to the nfs server). The pauses occur when mythtv fetches the next
> piece
>
>> of the video (or when the nfs client does). You can see my
> description on
>
>> my first post, if you'd like.
>
>
> OK, figured it was worth a shot.
>
>
> Last time I had a problem like that it turned out to be a flaky
> network
>
> card. Under heavy load it would drop a few packets, then NFS would
> sit
>
> around waiting for RPC retries.

Sorry for the big delay, but I was busy trying out things. The only setting I hadn't selected was "Always stream recordings from the backend". Turning it on didn't change anything.

I also tried cifs mount instead of nfs. Still pauses.

The nfs server (again) is now opensuse 11.2, 2.6.31.5 kernel. Still pauses. (By the way, trying it I ran into the "no keyboard + mouse" bug. It is solved by entering ' Option "AutoAddDevices" "Off" ' under Serverflags in xorg.conf. Google helps!)

I was wrong about the extra cpu activity during the pauses, it is clearly spiking. The nfs server is idle the rest of the time.

I even uninstalled the avg antivirus I had installed, just in case. No improvement. There are pauses, still.

I changed my ext3 filesystem to ext4. Still pauses.

My nfs server cpu is a Intel(R) Core(TM)2 Duo CPU E4500 @ 2.20GHz. It should be able to handle easily this kind of lvm/raid5 configuration. The network through-output is 10~12mb/s. It's just with mythtv video that I have these pauses.

I have already ordered a Q9400 Quad Core cpu ( I have been looking for an excuse, anyway ), should be here it 3-4 days - the retailer is out of stock.

If any developers are reading this, is there a remotely remote chance that myth is asking for the rest of the video when the buffer I assume it uses is too low, not allowing for any latency (network or filesystem?). If this is the case, is there a way to change this?

I am really running out of ideas, but if I find the time (kids + wife allowing) I will revert myth to a>2 month backup and try again. That will be the last resort!

Thanks for reading this.

Yianni.

_________________________________________________________________
Νέα Windows 7: Απλοποιήστε τις καθημερινές σας εργασίες. Βρείτε τον κατάλληλο υπολογιστή για εσάς.
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yiannividalis at hotmail

Nov 21, 2009, 7:38 AM

Post #19 of 19 (1201 views)
Permalink

Re: nfs pauses [In reply to]

----------------------------------------
> From: yiannividalis [at] hotmail
> To: mythtv-users [at] mythtv
> Date: Mon, 16 Nov 2009 18:16:16 +0200
> Subject: Re: [mythtv-users] nfs pauses
>
>
>
>
> ________________________________
>> Date: Fri, 13 Nov 2009 17:20:03 -0800
>> To: mythtv-users [at] mythtv
>> From: mache [at] creeger
>> Subject: Re: [mythtv-users] nfs pauses
>>
>>
>>
>> What do you have under "General Playback
>> (1/9)?
>>
>>
>> I have the following items checked.
>>
>>
>> Extra Audio Buffering
>>
>> Clear saved position on playback
>>
>> Alternate clear saved position
>>
>> Jump to Program OSD
>>
>> Always stream recordings from the backend
>>
>> Enable picture controls
>>
>>
>> The checking of "Use video as a timebase", may cause this type
>> of problem.
>>
>>
>> -- Mache
>>
>>
>> At 11:35 AM 11/13/2009, David Brodbeck wrote:
>>
>> On Fri, November 13, 2009 11:22
>> am, Yianni Vidalis wrote:
>>
>>> There was no extra cpu activity during the pauses. Also, the
>> network
>>
>>> activity was flat when no pause was occuring (nothing else was
>> moving from
>>
>>> or to the nfs server). The pauses occur when mythtv fetches the next
>> piece
>>
>>> of the video (or when the nfs client does). You can see my
>> description on
>>
>>> my first post, if you'd like.
>>
>>
>> OK, figured it was worth a shot.
>>
>>
>> Last time I had a problem like that it turned out to be a flaky
>> network
>>
>> card. Under heavy load it would drop a few packets, then NFS would
>> sit
>>
>> around waiting for RPC retries.
>
> Sorry for the big delay, but I was busy trying out things. The only setting I hadn't selected was "Always stream recordings from the backend". Turning it on didn't change anything.
>
> I also tried cifs mount instead of nfs. Still pauses.
>
> The nfs server (again) is now opensuse 11.2, 2.6.31.5 kernel. Still pauses. (By the way, trying it I ran into the "no keyboard + mouse" bug. It is solved by entering ' Option "AutoAddDevices" "Off" ' under Serverflags in xorg.conf. Google helps!)
>
> I was wrong about the extra cpu activity during the pauses, it is clearly spiking. The nfs server is idle the rest of the time.
>
> I even uninstalled the avg antivirus I had installed, just in case. No improvement. There are pauses, still.
>
> I changed my ext3 filesystem to ext4. Still pauses.
>
> My nfs server cpu is a Intel(R) Core(TM)2 Duo CPU E4500 @ 2.20GHz. It should be able to handle easily this kind of lvm/raid5 configuration. The network through-output is 10~12mb/s. It's just with mythtv video that I have these pauses.
>
> I have already ordered a Q9400 Quad Core cpu ( I have been looking for an excuse, anyway ), should be here it 3-4 days - the retailer is out of stock.
>
> If any developers are reading this, is there a remotely remote chance that myth is asking for the rest of the video when the buffer I assume it uses is too low, not allowing for any latency (network or filesystem?). If this is the case, is there a way to change this?
>
> I am really running out of ideas, but if I find the time (kids + wife allowing) I will revert myth to a>2 month backup and try again. That will be the last resort!
>
> Thanks for reading this.
>
> Yianni.
>
> _________________________________________________________________
> Νέα Windows 7: Απλοποιήστε τις καθημερινές σας εργασίες. Βρείτε τον κατάλληλο υπολογιστή για εσάς.
> http://windows.microsoft.com/shop
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

Well, just to finish the story:

Reverting to an old (24 September) myth svn backup cured nothing. Back to current version.

The Q9400 cpu didn't help much, either - mythwise, that is. The system is VERY fast now for everyday use.

I copied all my data to another hd, removed the logical volume and left only the raid 5 array. I then created an ext4 filesystem on that and copied the data back.

All is ok now, no latency, no pauses.

This will be a lesson for the future for me, "Unless you get REALLY FAST hds, (I guess velociraptors could do it, but I have 4 x WDCWD6400AAVS) DON'T put lvm on top of a raid 5 array". The latency is ok for everyday use, you won't even notice it, but trying to play H.264 5.1 video through the network (nfs or cifs) using myth, nooooo.

Yianni.

_________________________________________________________________
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