[mythtv-users] IOBOUND error over cifs (to nslu2)

Wed Mar 1 15:02:56 UTC 2006

That was already done... de-underclock and running unslung 5.5 beta. 
Some people were saying on this forum that cifs would be better than
NFS for myth, that's why I'm not using NFS on my slug.

I'll try NFS, will see...  I might just reformat my box this weekend
and give linux a bit more space to store a few full show and then copy
it to the slug.

Steve M.

On 2/28/06, Brian Wood <beww at beww.org> wrote:
>
> On Feb 28, 2006, at 8:37 PM, Steve Malenfant wrote:
>
> > WA is always using most of the CPU time...
> >
> > procs -----------memory---------- ---swap-- -----io---- --system--
> > ----cpu----
> >  r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs
> > us sy id wa
> >  0  2    148  15012  20464 863052    0    0     0   216 3464  3993
> > 4  7  0 89
> >  1  2    148  15012  20464 863052    0    0     0     0 3140  3462
> > 0  1  0 99
> >  0  2    148  14996  20440 863108    0    0     0   208 3397  3688
> > 3  7  0 90
> >  0  2    148  14968  20440 863108    0    0     0    16 3481  3695
> > 1  6  0 93
> >  0  2    148  15036  20456 862996    0    0     0   208 3460  3758
> > 4  6  0 90
> >
> > Now I'm getting these nice messages :
> > 2006-02-28 22:28:18.104 DevRdB(0) Error: Driver buffers overflowed
> >
> > I guess I can't use the NSLU2 for recording.  What I usually do is
> > move the files I won't watch for a while on it, cause reading is fine.
>
> What software/firmware are you using on the slug (NSLU2)? The stock
> Linksys firmware is not optimum as far as performance is concerned.
> Also, have you "de-underclocked" your slug? The CPU is in fact a
> 266Mhz. chip, which Linksys has for some strange reason throttled
> down to 133. By removing one resistor you can get the speed back to
> 266 for a bit of a performance boost.
>
> Check out :
> http://groups.yahoo.com/group/nslu2-linux/
>
> For several options to the stock firmware, including a Debian port.
> There is also some information on optimizing performance as well as
> recording video. You might also be able to use NFS instead of samba
> for a bit of help as well.
>
> I apologize if you were already aware of these options. I'm running
> several slugs, one as a mail server and another as a (somewhat slow)
> Apache box. It's a lot of machine for $90.
>
> >
> > Some high WA happens as well I try to watch 1 program and record 2
> > programs at once on my backend.  Poor 1.6 Ghz server can't handle 50
> > mbits recording/playing, but handles ftp at 400 mbits...
> >
> > Steve M.
> >
> > On 2/28/06, Brandon Stoll <mrmagoo at mrmagoo.org> wrote:
> >> On 2/28/06, Steve Malenfant <smalenfant at gmail.com> wrote:
> >>> I have a frontend and a backend.  My backend has 2 HD tuner that
> >>> record on the local disk, that works just fine.
> >>>
> >>> My frontend has been transformed into slave backend, it has 1 HD
> >>> tuner
> >>> in it.  I want to use it to record an extra program.  The problem is
> >>> that I get IOBOUND error to the backend and that my frontend has
> >>> only
> >>> a small 10G partition for linux (bad choice, I know).
> >>>
> >>> So I'm using my nslu2 mounted with cifs : //nslu2//public on
> >>> /mnt/nslu2 type cifs (rw,mand)
> >>>
> >>> While I'm recording an HD program, top shows this :
> >>>
> >>> Cpu(s):  0.3% us,  3.0% sy,  0.0% ni,  0.0% id, 94.7% wa,  2.0%
> >>> hi,  0.0% si
> >>>
> >>> I've got a few errors in my log that looks like this :
> >>> 2006-02-28 18:54:33.218 TFW, Error: Write() -- IOBOUND begin cnt
> >>> (9400) free(555)
> >>> 2006-02-28 18:54:33.221 TFW, Error: Write() -- IOBOUND end
> >>> 2006-02-28 18:54:33.315 TFW, Error: Write() -- IOBOUND begin cnt
> >>> (9400)
> >>> free(3123)
> >>> 2006-02-28 18:54:33.321 TFW, Error: Write() -- IOBOUND end
> >>>
> >>> They lasted only for 4 seconds and the rest of the recording
> >>> seems to
> >>> have recorded just fine.
> >>>
> >>> I'm not sure that I would be able to use the frontend while I'm
> >>> recording.  I know the nslu2 isn't fast, although it can handle at
> >>> least 40 mbits/sec.
> >>>
> >>> Anybody knows why the "WA" is so high?
> >>> A larger ring buffer would help here?
> >>>
> >>> Thanks.
> >>>
> >>> Steve M.
> >>
> >>
> >> Have you tried increasing/decreasing the "HD Ringbuffer" setting in
> >> the general settings (all backends have to be restarted if you change
> >> this I believe)?  Also make sure the nics are at 100mb/full-duplex
> >> (ethtool).
> >>
> >> running `vmstat 1` should give you a little bit better information on
> >> resource usage.  The WA is how much time is being spent waiting for
> >> disk read/writes.  Increasing the buffer size isn't going to help you
> >> if you are seeing high WA times for the whole recording.
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> >>
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