* RE: Disk copy, last sector problem
@ 2004-06-24 7:32 David Balazic
2004-06-29 22:16 ` Bill Davidsen
0 siblings, 1 reply; 6+ messages in thread
From: David Balazic @ 2004-06-24 7:32 UTC (permalink / raw)
To: Philippe Troin, 'Andries Brouwer'
Cc: David Balazic, 'Linux-Kernel@vger.kernel.org'
> From: Andries Brouwer[SMTP:aebr@win.tue.nl]
>
> On Tue, Jun 22, 2004 at 09:52:54AM -0700, Philippe Troin wrote:
> > David Balazic <david.balazic@hermes.si> writes:
> >
> > > Hi!
> > >
> > > cat /dev/hda > /dev/hdc
> > >
> > > This would not copy the entire disk as expected, but miss the last
> sector if
> > > the number of
> > > sectors on hda is odd. ( I used "cat" becasue it has the simplest
> syntax,
> > > "dd" and other behave the same ).
> > > Has this been fixed recently ?
> > > What about suppport of other sectors sizes, like 8kb ?
> >
> > Have you tried setting the device block size to its sector size?
> >
> > blockdev --setbsz $(blockdev --getss /dev/...) /dev/...
>
> If I understand correctly David is not reporting a problem, but
> vaguely recalls that there was a problem in this area long ago,
> and asks whet the current status is.
>
> (Yes, today things are better, but not perfect yet :-))
>
So the copy will still miss the last sector ?
But the blockdev command is a working workaround ?
Are there any downsides of setting the block size to
512 bytes right at boot for all hard drives ?
What about 8kb sectors, do they work ?
Thanks for your time ;-)
David
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Disk copy, last sector problem
2004-06-24 7:32 Disk copy, last sector problem David Balazic
@ 2004-06-29 22:16 ` Bill Davidsen
2004-06-29 22:19 ` viro
0 siblings, 1 reply; 6+ messages in thread
From: Bill Davidsen @ 2004-06-29 22:16 UTC (permalink / raw)
To: linux-kernel
David Balazic wrote:
>>From: Andries Brouwer[SMTP:aebr@win.tue.nl]
>>
>>On Tue, Jun 22, 2004 at 09:52:54AM -0700, Philippe Troin wrote:
>>
>>>David Balazic <david.balazic@hermes.si> writes:
>>>
>>>
>>>>Hi!
>>>>
>>>>cat /dev/hda > /dev/hdc
>>>>
>>>>This would not copy the entire disk as expected, but miss the last
>>
>>sector if
>>
>>>>the number of
>>>>sectors on hda is odd. ( I used "cat" becasue it has the simplest
>>
>>syntax,
>>
>>>>"dd" and other behave the same ).
>>>>Has this been fixed recently ?
>>>>What about suppport of other sectors sizes, like 8kb ?
>>>
>>>Have you tried setting the device block size to its sector size?
>>>
>>> blockdev --setbsz $(blockdev --getss /dev/...) /dev/...
>>
>>If I understand correctly David is not reporting a problem, but
>>vaguely recalls that there was a problem in this area long ago,
>>and asks whet the current status is.
>>
>>(Yes, today things are better, but not perfect yet :-))
>>
>
> So the copy will still miss the last sector ?
> But the blockdev command is a working workaround ?
> Are there any downsides of setting the block size to
> 512 bytes right at boot for all hard drives ?
> What about 8kb sectors, do they work ?
Given that the change from 1k to 4k, I suspect that going to 512 will
suck rocks off the bottom of the ocean in terms of performance. I don't
think that 8k works in 2.4, it didn't work in my 2.6, but the error was
"device busy" so it may not be related to anything but having no spare
drive.
--
-bill davidsen (davidsen@tmr.com)
"The secret to procrastination is to put things off until the
last possible moment - but no longer" -me
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Disk copy, last sector problem
2004-06-29 22:16 ` Bill Davidsen
@ 2004-06-29 22:19 ` viro
0 siblings, 0 replies; 6+ messages in thread
From: viro @ 2004-06-29 22:19 UTC (permalink / raw)
To: Bill Davidsen; +Cc: linux-kernel
On Tue, Jun 29, 2004 at 06:16:25PM -0400, Bill Davidsen wrote:
> >So the copy will still miss the last sector ?
> >But the blockdev command is a working workaround ?
> >Are there any downsides of setting the block size to
> >512 bytes right at boot for all hard drives ?
> >What about 8kb sectors, do they work ?
>
> Given that the change from 1k to 4k, I suspect that going to 512 will
> suck rocks off the bottom of the ocean in terms of performance. I don't
> think that 8k works in 2.4, it didn't work in my 2.6, but the error was
> "device busy" so it may not be related to anything but having no spare
> drive.
First of all, it *will* work without any "blockdev command" crap.
And no, performace is not a problem - we get requests immediately
merged and unlike regular files we don't spend time figuring out
where the hell next block is.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Disk copy, last sector problem
@ 2004-06-22 9:30 David Balazic
2004-06-22 16:52 ` Philippe Troin
0 siblings, 1 reply; 6+ messages in thread
From: David Balazic @ 2004-06-22 9:30 UTC (permalink / raw)
To: 'Linux-Kernel@vger.kernel.org'
Hi!
cat /dev/hda > /dev/hdc
This would not copy the entire disk as expected, but miss the last sector if
the number of
sectors on hda is odd. ( I used "cat" becasue it has the simplest syntax,
"dd" and other behave the same ).
Has this been fixed recently ?
What about suppport of other sectors sizes, like 8kb ?
Regards,
David Balažic
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David Balazic mailto:david.balazic@hermes.si
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Bill S. Preston, Esq. & "Ted" Theodore Logan
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Disk copy, last sector problem
2004-06-22 9:30 David Balazic
@ 2004-06-22 16:52 ` Philippe Troin
2004-06-23 17:59 ` Andries Brouwer
0 siblings, 1 reply; 6+ messages in thread
From: Philippe Troin @ 2004-06-22 16:52 UTC (permalink / raw)
To: David Balazic; +Cc: 'Linux-Kernel@vger.kernel.org'
David Balazic <david.balazic@hermes.si> writes:
> Hi!
>
> cat /dev/hda > /dev/hdc
>
> This would not copy the entire disk as expected, but miss the last sector if
> the number of
> sectors on hda is odd. ( I used "cat" becasue it has the simplest syntax,
> "dd" and other behave the same ).
> Has this been fixed recently ?
> What about suppport of other sectors sizes, like 8kb ?
Have you tried setting the device block size to its sector size?
blockdev --setbsz $(blockdev --getss /dev/...) /dev/...
Phil.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Disk copy, last sector problem
2004-06-22 16:52 ` Philippe Troin
@ 2004-06-23 17:59 ` Andries Brouwer
0 siblings, 0 replies; 6+ messages in thread
From: Andries Brouwer @ 2004-06-23 17:59 UTC (permalink / raw)
To: Philippe Troin; +Cc: David Balazic, 'Linux-Kernel@vger.kernel.org'
On Tue, Jun 22, 2004 at 09:52:54AM -0700, Philippe Troin wrote:
> David Balazic <david.balazic@hermes.si> writes:
>
> > Hi!
> >
> > cat /dev/hda > /dev/hdc
> >
> > This would not copy the entire disk as expected, but miss the last sector if
> > the number of
> > sectors on hda is odd. ( I used "cat" becasue it has the simplest syntax,
> > "dd" and other behave the same ).
> > Has this been fixed recently ?
> > What about suppport of other sectors sizes, like 8kb ?
>
> Have you tried setting the device block size to its sector size?
>
> blockdev --setbsz $(blockdev --getss /dev/...) /dev/...
If I understand correctly David is not reporting a problem, but
vaguely recalls that there was a problem in this area long ago,
and asks whet the current status is.
(Yes, today things are better, but not perfect yet :-))
^ permalink raw reply [flat|nested] 6+ messages in thread
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2004-06-24 7:32 Disk copy, last sector problem David Balazic
2004-06-29 22:16 ` Bill Davidsen
2004-06-29 22:19 ` viro
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2004-06-22 9:30 David Balazic
2004-06-22 16:52 ` Philippe Troin
2004-06-23 17:59 ` Andries Brouwer
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