Re: Re: [PATCH] dm-striped device sizes must be multiple of chunk-size

Re: Re: [PATCH] dm-striped device sizes must be multiple of chunk-size

[Kevin Corry]

On Wed March 22 2006 11:28 pm, Joseph Yasi wrote:
>     I am using the dmraid utility to detect and configure my Intel
> Software Raid RAID0 array.  When upgrading to 2.6.16 from 2.6.15, the
> system failed to boot because the device-mapper array was not built.
> I have traced the problem to this patch that limits dm-stripe to
> targets that are multiples of the chunk size.  I don't know whether to
> consider this a problem with device-mapper or with the Intel Software
> Raid BIOS that built the array.  Dmraid is giving me a target of
> 980460038 blocks with a chunk size of 256 blocks.  Is this a problem
> with device-mapper, the dmraid utility or the raid bios?  Should
> device-mapper handle striped targets that are not multiples of the
> chunk size?

Hmm...I obviously didn't expect dmraid to be creating such devices.

The kernel patch that was added to 2.6.16 is definitely correct. Dm-stripe 
should not allow creating a device with a size that's not a multiple of the 
chunk-size. To do so leaves a partial chunk at the end of each device. While 
at first glance this might not seem like a big deal, the striping 
calculations in the I/O path do not handle this situation (at least, not in 
the way you would think it should be handled), and cause I/O errors if you 
try to access the end of the stripe device.

> dmesg gives these pertinent lines:
> device-mapper: dm-stripe: Target length not divisible by chunk size.
> device-mapper: error adding target to table.
>
> dmsetup status
> isw_caejhbcidd_Volume03: 0 976173660 linear
> isw_caejhbcidd_Volume02: 0 4209030 linear
> isw_caejhbcidd_Volume01: 0 64197 linear
> isw_caejhbcidd_Volume0: 0 980460038 striped
>
> dmraid -s
> *** Group superset isw_caejhbcidd
> --> Active Subset
> name   : isw_caejhbcidd_Volume0
> size   : 980460038
> stride : 256
> type   : stripe
> status : ok
> subsets: 0
> devs   : 2
> spares : 0

In your example, your stripe device is 980460038 sectors, with a 256 sector 
chunk-size.This means the stripe device has 3829922 chunks, with 6 sectors 
left over (3 on each of the two devices, presumably). I would think that the 
BIOS intends that these last 3 sectors on each device should be striped with 
an effective chunk-size of 3 sectors. To do this, dmraid should set up a 
device with two targets, one with a chunk-size of 256, and one with a 
chunk-size of 3. The map would look something like:

0 980460032 striped 2 256 /dev/hda 0 /dev/hdb 0
980460032 6 striped 2 3 /dev/hda /dev/hdb 490230016

Unfortunately, this doesn't work either, because the chunk-size must be a 
power-of-2. So...since we know the second target in the map really represents 
only one "stripe", we could treat them as a concatenation of independent 
linear targets. So we end up with a map like this:

0 980460032 striped 2 256 /dev/hda 0 /dev/hdb 0
980460032 3 linear /dev/hda 490230016
980460032 3 linear /dev/hdb 490230016

I'm thinking that this mapping would do what the BIOS is actually intending. 
It ought to be relatively straight-forward to recognize this situation in 
dmraid and set up a mapping similar to the one above.

-- 
Kevin Corry
kevcorry@us.ibm.com
http://www.ibm.com/linux/
http://evms.sourceforge.net/

Re: Re: [PATCH] dm-striped device sizes must be multiple of chunk-size

[Heinz Mauelshagen]

Kevin,

I'm not convinced that a more complex mapping is needed.

Haven't seen the reported case so far with a lot of RAID0 metadata samples
users provided to me for various ATARAID flavours.

The RAID device size (which is smaller than the underlying device)
needs to be divisable w/o rest by the stride size IMO.

Guess I'm missing something about setting up the device size (rd->sectors)
correctly in the metadata format handler.

Investigating...

Heinz

On Fri, Mar 24, 2006 at 10:46:25PM -0600, Kevin Corry wrote:
> On Wed March 22 2006 11:28 pm, Joseph Yasi wrote:
> >     I am using the dmraid utility to detect and configure my Intel
> > Software Raid RAID0 array.  When upgrading to 2.6.16 from 2.6.15, the
> > system failed to boot because the device-mapper array was not built.
> > I have traced the problem to this patch that limits dm-stripe to
> > targets that are multiples of the chunk size.  I don't know whether to
> > consider this a problem with device-mapper or with the Intel Software
> > Raid BIOS that built the array.  Dmraid is giving me a target of
> > 980460038 blocks with a chunk size of 256 blocks.  Is this a problem
> > with device-mapper, the dmraid utility or the raid bios?  Should
> > device-mapper handle striped targets that are not multiples of the
> > chunk size?
> 
> Hmm...I obviously didn't expect dmraid to be creating such devices.
> 
> The kernel patch that was added to 2.6.16 is definitely correct. Dm-stripe 
> should not allow creating a device with a size that's not a multiple of the 
> chunk-size. To do so leaves a partial chunk at the end of each device. While 
> at first glance this might not seem like a big deal, the striping 
> calculations in the I/O path do not handle this situation (at least, not in 
> the way you would think it should be handled), and cause I/O errors if you 
> try to access the end of the stripe device.
> 
> > dmesg gives these pertinent lines:
> > device-mapper: dm-stripe: Target length not divisible by chunk size.
> > device-mapper: error adding target to table.
> >
> > dmsetup status
> > isw_caejhbcidd_Volume03: 0 976173660 linear
> > isw_caejhbcidd_Volume02: 0 4209030 linear
> > isw_caejhbcidd_Volume01: 0 64197 linear
> > isw_caejhbcidd_Volume0: 0 980460038 striped
> >
> > dmraid -s
> > *** Group superset isw_caejhbcidd
> > --> Active Subset
> > name   : isw_caejhbcidd_Volume0
> > size   : 980460038
> > stride : 256
> > type   : stripe
> > status : ok
> > subsets: 0
> > devs   : 2
> > spares : 0
> 
> In your example, your stripe device is 980460038 sectors, with a 256 sector 
> chunk-size.This means the stripe device has 3829922 chunks, with 6 sectors 
> left over (3 on each of the two devices, presumably). I would think that the 
> BIOS intends that these last 3 sectors on each device should be striped with 
> an effective chunk-size of 3 sectors. To do this, dmraid should set up a 
> device with two targets, one with a chunk-size of 256, and one with a 
> chunk-size of 3. The map would look something like:
> 
> 0 980460032 striped 2 256 /dev/hda 0 /dev/hdb 0
> 980460032 6 striped 2 3 /dev/hda /dev/hdb 490230016
> 
> Unfortunately, this doesn't work either, because the chunk-size must be a 
> power-of-2. So...since we know the second target in the map really represents 
> only one "stripe", we could treat them as a concatenation of independent 
> linear targets. So we end up with a map like this:
> 
> 0 980460032 striped 2 256 /dev/hda 0 /dev/hdb 0
> 980460032 3 linear /dev/hda 490230016
> 980460032 3 linear /dev/hdb 490230016
> 
> I'm thinking that this mapping would do what the BIOS is actually intending. 
> It ought to be relatively straight-forward to recognize this situation in 
> dmraid and set up a mapping similar to the one above.
> 
> -- 
> Kevin Corry
> kevcorry@us.ibm.com
> http://www.ibm.com/linux/
> http://evms.sourceforge.net/
> 
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Red Hat GmbH
Consulting Development Engineer                   Am Sonnenhang 11
Storage Development                               56242 Marienrachdorf
                                                  Germany
Mauelshagen@RedHat.com                            PHONE +49  171 7803392
                                                  FAX   +49 2626 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Re: Re: [PATCH] dm-striped device sizes must be multiple of chunk-size

[Heinz Mauelshagen]

Joseph,

can you send me the tar-archive of your metadata

	dmraid -rD
	tar jcvf isw-Joseph_Yasi-raid0.tar.bz2 *.{dat,size,offset)

for reference, please.

Heinz


On Wed, Mar 22, 2006 at 11:28:22PM -0600, Joseph Yasi wrote:
> Hello,
> 
>     I am using the dmraid utility to detect and configure my Intel
> Software Raid RAID0 array.  When upgrading to 2.6.16 from 2.6.15, the
> system failed to boot because the device-mapper array was not built. 
> I have traced the problem to this patch that limits dm-stripe to
> targets that are multiples of the chunk size.  I don't know whether to
> consider this a problem with device-mapper or with the Intel Software
> Raid BIOS that built the array.  Dmraid is giving me a target of
> 980460038 blocks with a chunk size of 256 blocks.  Is this a problem
> with device-mapper, the dmraid utility or the raid bios?  Should
> device-mapper handle striped targets that are not multiples of the
> chunk size?
> 
> Thank You,
> Joe Yasi
> 
> dmesg gives these pertinent lines:
> device-mapper: dm-stripe: Target length not divisible by chunk size.
> device-mapper: error adding target to table.
> 
> dmsetup status
> isw_caejhbcidd_Volume03: 0 976173660 linear
> isw_caejhbcidd_Volume02: 0 4209030 linear
> isw_caejhbcidd_Volume01: 0 64197 linear
> isw_caejhbcidd_Volume0: 0 980460038 striped
> 
> dmraid -s
> *** Group superset isw_caejhbcidd
> --> Active Subset
> name   : isw_caejhbcidd_Volume0
> size   : 980460038
> stride : 256
> type   : stripe
> status : ok
> subsets: 0
> devs   : 2
> spares : 0
> 
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Red Hat GmbH
Consulting Development Engineer                   Am Sonnenhang 11
Storage Development                               56242 Marienrachdorf
                                                  Germany
Mauelshagen@RedHat.com                            PHONE +49  171 7803392
                                                  FAX   +49 2626 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Re: Re: [PATCH] dm-striped device sizes must be multiple of chunk-size

[Heinz Mauelshagen]

Dwaine,

can you please send me your metadata for refernence as well so
that I can confirm that my fix is good for bz #186842 ?

Thanks,
Heinz

On Sun, Mar 26, 2006 at 12:01:17AM +0000, Dwaine Garden wrote:
> Kevin Corry <kevcorry <at> us.ibm.com> writes:
> > 
> > I'm thinking that this mapping would do what the BIOS is actually intending. 
> > It ought to be relatively straight-forward to recognize this situation in 
> > dmraid and set up a mapping similar to the one above.
> > 
> 
> I have the same problem.  How would you resolve this?
> 
> Dwaine
> 
> 
> 
> 
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Red Hat GmbH
Consulting Development Engineer                   Am Sonnenhang 11
Storage Development                               56242 Marienrachdorf
                                                  Germany
Mauelshagen@RedHat.com                            PHONE +49  171 7803392
                                                  FAX   +49 2626 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Re: Re: [PATCH] dm-striped device sizes must be multiple of chunk-size

[Heinz Mauelshagen]

Kevin,

got a fix in a central location (activate.c) which looks like it cuts the issue.
Just waiting for metadata samples of reporters to get in to confirm.

Heinz

On Tue, Mar 28, 2006 at 02:08:13PM +0200, Heinz Mauelshagen wrote:
> 
> Kevin,
> 
> I'm not convinced that a more complex mapping is needed.
> 
> Haven't seen the reported case so far with a lot of RAID0 metadata samples
> users provided to me for various ATARAID flavours.
> 
> The RAID device size (which is smaller than the underlying device)
> needs to be divisable w/o rest by the stride size IMO.
> 
> Guess I'm missing something about setting up the device size (rd->sectors)
> correctly in the metadata format handler.
> 
> Investigating...
> 
> Heinz
> 
> On Fri, Mar 24, 2006 at 10:46:25PM -0600, Kevin Corry wrote:
> > On Wed March 22 2006 11:28 pm, Joseph Yasi wrote:
> > >     I am using the dmraid utility to detect and configure my Intel
> > > Software Raid RAID0 array.  When upgrading to 2.6.16 from 2.6.15, the
> > > system failed to boot because the device-mapper array was not built.
> > > I have traced the problem to this patch that limits dm-stripe to
> > > targets that are multiples of the chunk size.  I don't know whether to
> > > consider this a problem with device-mapper or with the Intel Software
> > > Raid BIOS that built the array.  Dmraid is giving me a target of
> > > 980460038 blocks with a chunk size of 256 blocks.  Is this a problem
> > > with device-mapper, the dmraid utility or the raid bios?  Should
> > > device-mapper handle striped targets that are not multiples of the
> > > chunk size?
> > 
> > Hmm...I obviously didn't expect dmraid to be creating such devices.
> > 
> > The kernel patch that was added to 2.6.16 is definitely correct. Dm-stripe 
> > should not allow creating a device with a size that's not a multiple of the 
> > chunk-size. To do so leaves a partial chunk at the end of each device. While 
> > at first glance this might not seem like a big deal, the striping 
> > calculations in the I/O path do not handle this situation (at least, not in 
> > the way you would think it should be handled), and cause I/O errors if you 
> > try to access the end of the stripe device.
> > 
> > > dmesg gives these pertinent lines:
> > > device-mapper: dm-stripe: Target length not divisible by chunk size.
> > > device-mapper: error adding target to table.
> > >
> > > dmsetup status
> > > isw_caejhbcidd_Volume03: 0 976173660 linear
> > > isw_caejhbcidd_Volume02: 0 4209030 linear
> > > isw_caejhbcidd_Volume01: 0 64197 linear
> > > isw_caejhbcidd_Volume0: 0 980460038 striped
> > >
> > > dmraid -s
> > > *** Group superset isw_caejhbcidd
> > > --> Active Subset
> > > name   : isw_caejhbcidd_Volume0
> > > size   : 980460038
> > > stride : 256
> > > type   : stripe
> > > status : ok
> > > subsets: 0
> > > devs   : 2
> > > spares : 0
> > 
> > In your example, your stripe device is 980460038 sectors, with a 256 sector 
> > chunk-size.This means the stripe device has 3829922 chunks, with 6 sectors 
> > left over (3 on each of the two devices, presumably). I would think that the 
> > BIOS intends that these last 3 sectors on each device should be striped with 
> > an effective chunk-size of 3 sectors. To do this, dmraid should set up a 
> > device with two targets, one with a chunk-size of 256, and one with a 
> > chunk-size of 3. The map would look something like:
> > 
> > 0 980460032 striped 2 256 /dev/hda 0 /dev/hdb 0
> > 980460032 6 striped 2 3 /dev/hda /dev/hdb 490230016
> > 
> > Unfortunately, this doesn't work either, because the chunk-size must be a 
> > power-of-2. So...since we know the second target in the map really represents 
> > only one "stripe", we could treat them as a concatenation of independent 
> > linear targets. So we end up with a map like this:
> > 
> > 0 980460032 striped 2 256 /dev/hda 0 /dev/hdb 0
> > 980460032 3 linear /dev/hda 490230016
> > 980460032 3 linear /dev/hdb 490230016
> > 
> > I'm thinking that this mapping would do what the BIOS is actually intending. 
> > It ought to be relatively straight-forward to recognize this situation in 
> > dmraid and set up a mapping similar to the one above.
> > 
> > -- 
> > Kevin Corry
> > kevcorry@us.ibm.com
> > http://www.ibm.com/linux/
> > http://evms.sourceforge.net/
> > 
> > --
> > dm-devel mailing list
> > dm-devel@redhat.com
> > https://www.redhat.com/mailman/listinfo/dm-devel

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Red Hat GmbH
Consulting Development Engineer                   Am Sonnenhang 11
Storage Development                               56242 Marienrachdorf
                                                  Germany
Mauelshagen@RedHat.com                            PHONE +49  171 7803392
                                                  FAX   +49 2626 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Re: [PATCH] dm-striped device sizes must be multiple of chunk-size

[Peyrotau Yannick]

Hi, I have the same problem too when i try to upgrade to 2.6.16 kernel.

My motherbord is ASUS A8N-E with a nvidia raid chip.

I have make an archive with my metadata at this adress :
http://crashteam1.free.fr/metadata/metadata_isw-Yannick_Peyrotau-raid0.tar.bz2

Can i resolve it ?


Thanks,
Yannick

> Dwaine,
>
> can you please send me your metadata for refernence as well so
> that I can confirm that my fix is good for bz #186842 ?
>
> Thanks,
> Heinz
>
> On Sun, Mar 26, 2006 at 12:01:17AM +0000, Dwaine Garden wrote:
> > Kevin Corry <kevcorry <at> us.ibm.com> writes:
> > >
> > > I'm thinking that this mapping would do what the BIOS is actually
> > > intending.
> > > It ought to be relatively straight-forward to recognize this
> > > situation in
> > > dmraid and set up a mapping similar to the one above.
> > >
> >
> > I have the same problem.  How would you resolve this?
> >
> > Dwaine
> >
> >
> >
> >
> > --
> > dm-devel mailing list
> > dm-devel redhat com
> > https://www.redhat.com/mailman/listinfo/dm-devel

Re: Re: [PATCH] dm-striped device sizes must be multiple of chunk-size

[Heinz Mauelshagen]

On Wed, May 31, 2006 at 06:17:58PM +0200, Peyrotau Yannick wrote:
> Hi, I have the same problem too when i try to upgrade to 2.6.16 kernel.
> 
> My motherbord is ASUS A8N-E with a nvidia raid chip.
> 
> I have make an archive with my metadata at this adress :
> http://crashteam1.free.fr/metadata/metadata_isw-Yannick_Peyrotau-raid0.tar.bz2
> 
> Can i resolve it ?

Pull dmraid-1.0.0.rc11 from FC5.

Heinz

> 
> 
> Thanks,
> Yannick
> 
> >Dwaine,
> >
> >can you please send me your metadata for refernence as well so
> >that I can confirm that my fix is good for bz #186842 ?
> >
> >Thanks,
> >Heinz
> >
> >On Sun, Mar 26, 2006 at 12:01:17AM +0000, Dwaine Garden wrote:
> >> Kevin Corry <kevcorry <at> us.ibm.com> writes:
> >> >
> >> > I'm thinking that this mapping would do what the BIOS is actually
> >> > intending.
> >> > It ought to be relatively straight-forward to recognize this
> >> > situation in
> >> > dmraid and set up a mapping similar to the one above.
> >> >
> >>
> >> I have the same problem.  How would you resolve this?
> >>
> >> Dwaine
> >>
> >>
> >>
> >>
> >> --
> >> dm-devel mailing list
> >> dm-devel redhat com
> >> https://www.redhat.com/mailman/listinfo/dm-devel
> 
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Red Hat GmbH
Consulting Development Engineer                   Am Sonnenhang 11
Storage Development                               56242 Marienrachdorf
                                                  Germany
Mauelshagen@RedHat.com                            PHONE +49  171 7803392
                                                  FAX   +49 2626 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Re: Re: [PATCH] dm-striped device sizes must be multiple of chunk-size

[Dwaine Garden]

[-- Attachment #1.1: Type: text/plain, Size: 1471 bytes --]

There is a new rpm for dmraid that you can install that will resolve your issue.   rc11.

----- Original Message ----
From: Peyrotau Yannick <peyrotau.yannick@free.fr>
To: dm-devel@redhat.com
Sent: Tuesday, May 30, 2006 9:14:19 AM
Subject: [dm-devel] Re: [PATCH] dm-striped device sizes must be multiple of chunk-size

Hi, I have the same problem too when i try to upgrade to 2.6.16 kernel.

My motherbord is ASUS A8N-E with a nvidia raid chip.

I have make an archive with my metadata at this adress :
http://crashteam1.free.fr/metadata/metadata_isw-Yannick_Peyrotau-raid0.tar.bz2

Can i resolve it ?


Thanks,
Yannick

 > Dwaine,
 >
 > can you please send me your metadata for refernence as well so
 > that I can confirm that my fix is good for bz #186842 ?
 >
 > Thanks,
 > Heinz
 >
 > On Sun, Mar 26, 2006 at 12:01:17AM +0000, Dwaine Garden wrote:
 > > Kevin Corry <kevcorry <at> us.ibm.com> writes:
 > > >
 > > > I'm thinking that this mapping would do what the BIOS is actually
 > > > intending.
 > > > It ought to be relatively straight-forward to recognize this
 > > > situation in
 > > > dmraid and set up a mapping similar to the one above.
 > > >
 > >
 > > I have the same problem.  How would you resolve this?
 > >
 > > Dwaine
 > >
 > >
 > >
 > >
 > > --
 > > dm-devel mailing list
 > > dm-devel redhat com
 > > https://www.redhat.com/mailman/listinfo/dm-devel

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel




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