CentOS - Apr 2007 - CentOS5 consistent media check failures 2 - 6.

Folks,

As much as I hate to, I feel I need to post my long story and ask help.

Shortly after the release announcement, I kicked off rtorrent and
downloaded the CD and DVD images. Since my cable provider does my
"throttling", I disabled throttling and shared for several days,
"returning" several GBs at no objectionable loss I could discern.

While that was going on, I used cdrecord (don't jump to conclusions
here, read on) via CLI to burn the CDs. This on a fully-up-to-date
CentOS... well here

    uname -a
    Linux centos01.homegroannetworking 2.6.9-42.0.10.EL #1 Tue Feb 27
    09:24:42 EST 2007 i686 athlon i386 GNU/Linux

    $ lsb_release -a
    LSB Version:    :core-3.0-ia32:core-3.0-noarch:graphics-3.0-
        ia32:graphics-3.0-noarch
    Distributor ID: CentOS
    Description:    CentOS release 4.4 (Final)
    Release:        4.4
    Codename:       Final

CD writer is a generic 52x24x52x that I have used to burn many CDs
before w/o problems. On this unit and the other I'll mention, the writer
is master on IDE channel 2. Neither has an HD on that channel currently.
The other unit has SATA drives and the writer is again on IDE 2 by
itself.

Disc 1 passes media check and 2 - 6 fail consistently. Checks OK:

    ...CentOS-5.0-Old]$ md5sum -c md5sum.txt
    CentOS-5.0-i386-bin-1of6.iso: OK
    CentOS-5.0-i386-bin-2of6.iso: OK
    CentOS-5.0-i386-bin-3of6.iso: OK
    CentOS-5.0-i386-bin-4of6.iso: OK
    CentOS-5.0-i386-bin-5of6.iso: OK
    CentOS-5.0-i386-bin-6of6.iso: OK
    CentOS-5.0-i386-bin-DVD.iso: OK

IIRC, I also used the sha1 check (can't recall the command ATM) and it
also passed.

"NP" says I! I'll copy 'em over to my LFS machine and burn on
the Lite-
on DVD/CD* burner.

Same results.

Hmph. OK. Rtorrent unreliable (don't giggle - there's a difference in
the images as evidenced by "cmp" below)? Download all but the DVD
directly from the UofGA mirror. Save them in ...CentOS-New. Do similar
things.

    ...CentOS-5.0-New]$ md5sum -c md5sum.txt
    CentOS-5.0-i386-bin-1of6.iso: OK
    CentOS-5.0-i386-bin-2of6.iso: OK
    CentOS-5.0-i386-bin-3of6.iso: OK
    CentOS-5.0-i386-bin-4of6.iso: OK
    CentOS-5.0-i386-bin-5of6.iso: OK
    CentOS-5.0-i386-bin-6of6.iso: OK
    md5sum: CentOS-5.0-i386-bin-DVD.iso: No such file or directory
        CentOS-5.0-i386-bin-DVD.iso: FAILED open or read
    md5sum: WARNING: 1 of 7 listed files could not be read

Burned the CDs again. Media checks same as before - 1st passes and all
others fail. Did again on the LFS machine, same results.

All media as RW, some <=12x, some <=4x speeds. Was rewriting over media
previously used for CentOS 4.0 install (keeping 4.3 CDs available) and
other miscellaneous previously used RW CDs.

Well... maybe they are bad now? All the ones I tried?! Unlikely. But be
the type to avoid assumptions, burned disc 2 again on new media. It
still fails.

Jorge, in his long-running condemnation of Linux kernel SCSI
implementations, again mentions his usual in the docs he provides and
specifically states that kernel >=2.5 has problems (at least the rants
about the wort-ever SCSI implementations have abated). So I figure I'll
use something that does not involve CLI.

BTW, by now I've learned that there are differences between the rtorrent
created and downloaded-from-mirror images.

So I go to my trusty CentOS desktop, get nautilus going, right the disc
2 image and write to CD.

No improvement.

Last data point. Right after I downloaded from the UofGA mirror, I did a
cmp. All the rtorrent vs direct download images showed a byte difference
at offset 32768 of "line 1". My rtorrent was still running (IIRC)
serving others. OMG! Am I delivering corrupted images to many other
users!

I immediately shut down rtorrent.

When I do the cmp *now*, now differences are noted.

I checked cable seating on the "target" machine. OK. I tried reading
the
CDs on the same unit(s) that created them.

I'm now suspecting "wetware" problems. ATM, I probably can't
see the
forest for the trees.

Any thoughts, wisecracks, suggestions are welcome.

TIA
--
Bill

On Sun, 2007-04-22 at 15:07 -0400, William L. Maltby
wrote:
> Folks,
> 
> <snip>
> All media as RW, some <=12x, some <=4x speeds. Was rewriting over
media
> previously used for CentOS 4.0 install (keeping 4.3 CDs available) and
> other miscellaneous previously used RW CDs.
Clarification: each set consisted of the same-speed media.

<snip>
> So I go to my trusty CentOS desktop, get nautilus going, right the disc
                                                                ^
click
> 2 image and write to CD.
> 
> No improvement.
>
> Last data point. Right after I downloaded from the UofGA mirror, I did a
> cmp. All the rtorrent vs direct download images showed a byte difference
> at offset 32768 of "line 1". My rtorrent was still running (IIRC)
> serving others. OMG! Am I delivering corrupted images to many other
> users!
> 
> I immediately shut down rtorrent.
> 
> When I do the cmp *now*, now differences are noted.
s/now d/no d/
> <snip>
--
Bill

William L. Maltby wrote:
> Folks,
> 
> As much as I hate to, I feel I need to post my long story and ask help.
> 
> Shortly after the release announcement, I kicked off rtorrent and
> downloaded the CD and DVD images. Since my cable provider does my
> "throttling", I disabled throttling and shared for several days,
> "returning" several GBs at no objectionable loss I could discern.
> 
> While that was going on, I used cdrecord (don't jump to conclusions
> here, read on) via CLI to burn the CDs. This on a fully-up-to-date
> CentOS... well here
> 
>     uname -a
>     Linux centos01.homegroannetworking 2.6.9-42.0.10.EL #1 Tue Feb 27
>     09:24:42 EST 2007 i686 athlon i386 GNU/Linux
> 
>     $ lsb_release -a
>     LSB Version:    :core-3.0-ia32:core-3.0-noarch:graphics-3.0-
>         ia32:graphics-3.0-noarch
>     Distributor ID: CentOS
>     Description:    CentOS release 4.4 (Final)
>     Release:        4.4
>     Codename:       Final
> 
> CD writer is a generic 52x24x52x that I have used to burn many CDs
> before w/o problems. On this unit and the other I'll mention, the
writer
> is master on IDE channel 2. Neither has an HD on that channel currently.
> The other unit has SATA drives and the writer is again on IDE 2 by
> itself.
> 
> Disc 1 passes media check and 2 - 6 fail consistently. Checks OK:
> 
>     ...CentOS-5.0-Old]$ md5sum -c md5sum.txt
>     CentOS-5.0-i386-bin-1of6.iso: OK
>     CentOS-5.0-i386-bin-2of6.iso: OK
>     CentOS-5.0-i386-bin-3of6.iso: OK
>     CentOS-5.0-i386-bin-4of6.iso: OK
>     CentOS-5.0-i386-bin-5of6.iso: OK
>     CentOS-5.0-i386-bin-6of6.iso: OK
>     CentOS-5.0-i386-bin-DVD.iso: OK
> 
> IIRC, I also used the sha1 check (can't recall the command ATM) and it
> also passed.
>
At one time I got media check errors on a particular DVD in a new drive 
sometimes but not others.

My solution? Don't do the media check, that way it can't fail:-) If the 
install works, who cares what media check says?

Why not burn boot.iso and do an NFS install? You don't need to burn the 
rest at all.



-- 

Cheers
John

-- spambait
1aaaaaaa at coco.merseine.nu  Z1aaaaaaa at coco.merseine.nu

Please do not reply off-list

On Sunday 22 April 2007, William L. Maltby wrote:
> Folks,
>
> As much as I hate to, I feel I need to post my long story and ask help.
[snip info about failed mediachecks]

Please see the thread starting at 
http://lists.centos.org/pipermail/centos/2005-March/003347.html

Short form answer: cdrecord needs to -pad to get good mediachecks 
consistently.
-- 
Lamar Owen
Director of Information Technology
Pisgah Astronomical Research Institute
1 PARI Drive
Rosman, NC  28772
(828)862-5554
www.pari.edu