RE: Linux Kernel 2.6.6 IDE shutdown problems.

RE: Linux Kernel 2.6.6 IDE shutdown problems.

[Justin Piszcz]

The problem is the 2.6.6 kernel muxed my drive and when it fscked upon 
reboot it deleted /etc/mtab and lilo.conf!

Luckily I restored them from a backup and now run 2.6.5 and it is working 
fine.

Linux 2.6.6 is a nightmare.

I am looking into the benchmark problem with 2.6.6 now.


--- In linux-kernel@yahoogroups.com, "Justin Piszcz" <jpiszcz@h...> wrote:
>Now whenever I reboot it says input/output errors when it tries to mount 
>the drive? I will look into this further.
>
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Re: Linux Kernel 2.6.6 IDE shutdown problems.

[Bartlomiej Zolnierkiewicz]

On Saturday 15 of May 2004 14:20, Justin Piszcz wrote:
> The problem is the 2.6.6 kernel muxed my drive and when it fscked upon
> reboot it deleted /etc/mtab and lilo.conf!

What fs are you using?

> Luckily I restored them from a backup and now run 2.6.5 and it is working
> fine.
>
> Linux 2.6.6 is a nightmare.
>
> I am looking into the benchmark problem with 2.6.6 now.
>
> --- In linux-kernel@yahoogroups.com, "Justin Piszcz" <jpiszcz@h...> wrote:
> >Now whenever I reboot it says input/output errors when it tries to mount
> >the drive? I will look into this further.

This errors are HARMLESS and CAN'T corrupt your data.
Please see http://bugme.osdl.org/show_bug.cgi?id=2672 for description+fix.

Cheers,
Bartlomiej

Re: Linux Kernel 2.6.6 IDE shutdown problems.

[Bill Davidsen]

Bartlomiej Zolnierkiewicz wrote:
> On Saturday 15 of May 2004 14:20, Justin Piszcz wrote:
> 
>>The problem is the 2.6.6 kernel muxed my drive and when it fscked upon
>>reboot it deleted /etc/mtab and lilo.conf!
> 
> 
> What fs are you using?
> 
> 
>>Luckily I restored them from a backup and now run 2.6.5 and it is working
>>fine.
>>
>>Linux 2.6.6 is a nightmare.
>>
>>I am looking into the benchmark problem with 2.6.6 now.
>>
>>--- In linux-kernel@yahoogroups.com, "Justin Piszcz" <jpiszcz@h...> wrote:
>>
>>>Now whenever I reboot it says input/output errors when it tries to mount
>>>the drive? I will look into this further.
> 
> 
> This errors are HARMLESS and CAN'T corrupt your data.
> Please see http://bugme.osdl.org/show_bug.cgi?id=2672 for description+fix.

I would think that if the drive didn't properly flush cache on shutdown 
that it might cause corruption. Feel free to tell me no drive would 
bahave like that ;-)

-- 
    -bill davidsen (davidsen@tmr.com)
"The secret to procrastination is to put things off until the
  last possible moment - but no longer"  -me

Re: Linux Kernel 2.6.6 IDE shutdown problems.

[Tom Vier]

On Mon, May 17, 2004 at 06:25:51PM -0400, Bill Davidsen wrote:
> I would think that if the drive didn't properly flush cache on shutdown 
> that it might cause corruption. Feel free to tell me no drive would 
> bahave like that ;-)

why not add a one or two second delay before? i doubt any drive holds its
writeback that long.

-- 
Tom Vier <tmv@comcast.net>
DSA Key ID 0x15741ECE

Re: Linux Kernel 2.6.6 IDE shutdown problems.

[Daniel Pittman]

On 24 May 2004, Tom Vier wrote:
> On Mon, May 17, 2004 at 06:25:51PM -0400, Bill Davidsen wrote:
>> I would think that if the drive didn't properly flush cache on
>> shutdown that it might cause corruption. Feel free to tell me no
>> drive would bahave like that ;-)
>
> why not add a one or two second delay before? i doubt any drive holds
> its writeback that long.

This was the solution adopted by IBM, for their Thinkpad laptop line, in
a BIOS update last year.  My system now delays two seconds before
turning off, with the stated purpose "avoiding disk corruption"...

        Daniel

-- 
The English have the most rigid code of immorality in the world.
        -- Malcom Bradbury, _Eating People is Wrong_

Re: Linux Kernel 2.6.6 IDE shutdown problems.

[Eric D. Mudama]

On Sun, May 23 at 22:41, Tom Vier wrote:
>On Mon, May 17, 2004 at 06:25:51PM -0400, Bill Davidsen wrote:
>> I would think that if the drive didn't properly flush cache on shutdown 
>> that it might cause corruption. Feel free to tell me no drive would 
>> bahave like that ;-)
>
>why not add a one or two second delay before? i doubt any drive holds its
>writeback that long.

That is an arbitrary delay that isn't guaranteed to work in all
workloads.

FLUSH CACHE is the way to do this, complain to vendors that don't
support flush cache and get them to fix their drives.  (Like how Bart
spoke to me and we both 1) worked out a solution for current drives
and 2) fixed the root case in all future firmwares)


Picture a nice fast drive doing 100 writes/second to the media... if
you give it over 200 writes at a time, it'll occupy your 2 seconds.
Newer drives with 8MB or larger buffers are certainly capable of
caching a lot more than 200 writes...

Drives are getting smarter so they can better work around these sorts
of cases, but FLUSH CACHE (EXT) is the only way that should be
guaranteed to work.

--eric


-- 
Eric D. Mudama
edmudama@mail.bounceswoosh.org

Re: Linux Kernel 2.6.6 IDE shutdown problems.

[Giuliano Pochini]

On Mon, 24 May 2004, Eric D. Mudama wrote:

> Picture a nice fast drive doing 100 writes/second to the media... if
> you give it over 200 writes at a time, it'll occupy your 2 seconds.
> Newer drives with 8MB or larger buffers are certainly capable of
> caching a lot more than 200 writes...

Quite unlikely. Usually disks have a big cache but it can hold a very
limited number of blocks. 8MB of cache is probably divided in 8 blocks
of 1MB each.


--
Giuliano.

Re: Linux Kernel 2.6.6 IDE shutdown problems.

[Bartlomiej Zolnierkiewicz]

On Tuesday 25 of May 2004 11:05, Giuliano Pochini wrote:
> On Mon, 24 May 2004, Eric D. Mudama wrote:
> > Picture a nice fast drive doing 100 writes/second to the media... if
> > you give it over 200 writes at a time, it'll occupy your 2 seconds.
> > Newer drives with 8MB or larger buffers are certainly capable of
> > caching a lot more than 200 writes...
>
> Quite unlikely. Usually disks have a big cache but it can hold a very
> limited number of blocks. 8MB of cache is probably divided in 8 blocks
> of 1MB each.

No.

Re: Linux Kernel 2.6.6 IDE shutdown problems.

[Eric D. Mudama]

On Tue, May 25 at 11:05, Giuliano Pochini wrote:
>
>
>On Mon, 24 May 2004, Eric D. Mudama wrote:
>
>> Picture a nice fast drive doing 100 writes/second to the media... if
>> you give it over 200 writes at a time, it'll occupy your 2 seconds.
>> Newer drives with 8MB or larger buffers are certainly capable of
>> caching a lot more than 200 writes...
>
>Quite unlikely. Usually disks have a big cache but it can hold a very
>limited number of blocks. 8MB of cache is probably divided in 8 blocks
>of 1MB each.

Sorry, but that isn't true, unless some company is just plain stupid.

Everyone has different metrics for cache granularity based on their
cache architecture, but I can assure you that 8x 1MB segments is off
by 1-2 orders of magnitude, and has been for years.

In practice, depending on the workload, there may appear to only be 8
active segments as drives today can merge cache segments or other
similar things (architectually dependant), but the worst-case (best
case?) is significantly more.

--eric



-- 
Eric D. Mudama
edmudama@mail.bounceswoosh.org

Re: Linux Kernel 2.6.6 IDE shutdown problems.

[Ian Stirling]

Bartlomiej Zolnierkiewicz wrote:
> On Tuesday 25 of May 2004 11:05, Giuliano Pochini wrote:
> 
>>On Mon, 24 May 2004, Eric D. Mudama wrote:
>>
>>>Picture a nice fast drive doing 100 writes/second to the media... if
>>>you give it over 200 writes at a time, it'll occupy your 2 seconds.
>>>Newer drives with 8MB or larger buffers are certainly capable of
>>>caching a lot more than 200 writes...
>>
>>Quite unlikely. Usually disks have a big cache but it can hold a very
>>limited number of blocks. 8MB of cache is probably divided in 8 blocks
>>of 1MB each.
> 
> 
> No.

It is indeed likely that the worst case is around 16000 writes, which if
on seperate tracks may take over 30 seconds to complete if done individually.

However, it's likely that any drive designer with a clue would allocate a
couple of journal tracks, so that the write cache and two backup copies can
be stored for replay when the drive is powered on again.

Why do I suspect that some designers don't have clue, or haven't really thought
enough about this case.

Re: Linux Kernel 2.6.6 IDE shutdown problems.

[Justin Piszcz]

ext2 on this box


>From: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
>To: "Justin Piszcz" <jpiszcz@hotmail.com>, linux-kernel@vger.kernel.org
>CC: apiszcz@solarrain.com
>Subject: Re: Linux Kernel 2.6.6 IDE shutdown problems.
>Date: Sat, 15 May 2004 15:06:20 +0200
>
>On Saturday 15 of May 2004 14:20, Justin Piszcz wrote:
> > The problem is the 2.6.6 kernel muxed my drive and when it fscked upon
> > reboot it deleted /etc/mtab and lilo.conf!
>
>What fs are you using?
>
> > Luckily I restored them from a backup and now run 2.6.5 and it is 
>working
> > fine.
> >
> > Linux 2.6.6 is a nightmare.
> >
> > I am looking into the benchmark problem with 2.6.6 now.
> >
> > --- In linux-kernel@yahoogroups.com, "Justin Piszcz" <jpiszcz@h...> 
>wrote:
> > >Now whenever I reboot it says input/output errors when it tries to 
>mount
> > >the drive? I will look into this further.
>
>This errors are HARMLESS and CAN'T corrupt your data.
>Please see http://bugme.osdl.org/show_bug.cgi?id=2672 for description+fix.
>
>Cheers,
>Bartlomiej
>

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Linux Kernel 2.6.6 IDE shutdown problems.

[Justin Piszcz]

Now whenever I reboot it says input/output errors when it tries to mount the 
drive? I will look into this further.

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