[linux-lvm] Advanced Format disks mixed with regular disks?

[linux-lvm] Advanced Format disks mixed with regular disks?

[Ron Johnson]

Hi,

Is there any concern with mixing 4KB-sector drives with 512-byte 
sector drives in the same LV?

Sincerely,
Ron
-- 
I prefer banana-flavored energy bars made from tofu.

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Mike Snitzer]

On Mon, Mar 14 2011 at 12:47pm -0400,
Ron Johnson <ron.l.johnson@cox.net> wrote:

> Hi,
> 
> Is there any concern with mixing 4KB-sector drives with 512-byte
> sector drives in the same LV?

Both LVM2 and Device Mapper have been updated to accommodate stacking
such a mix of drives.

See this for a bit more detail:
http://people.redhat.com/msnitzer/docs/io-limits.txt

Particularly, the "Stacking I/O Limits" section.

The concern raised for partial (4k) writes to the 512b drive was
discussed a bit more here: http://lkml.org/lkml/2010/2/22/295

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Les Mikesell]

On 3/14/2011 12:17 PM, Mike Snitzer wrote:
>
>> Is there any concern with mixing 4KB-sector drives with 512-byte
>> sector drives in the same LV?
>
> Both LVM2 and Device Mapper have been updated to accommodate stacking
> such a mix of drives.
>
> See this for a bit more detail:
> http://people.redhat.com/msnitzer/docs/io-limits.txt
>
> Particularly, the "Stacking I/O Limits" section.
>
> The concern raised for partial (4k) writes to the 512b drive was
> discussed a bit more here: http://lkml.org/lkml/2010/2/22/295

Are there any version-level hints about when/where these changes appear 
and come together in the real world (i.e. distributions like RHEL, 
debian, Ubuntu)?

-- 
   Les Mikesell
    lesmikesell@gmail.com

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Mike Snitzer]

On Mon, Mar 14 2011 at  1:32pm -0400,
Les Mikesell <lesmikesell@gmail.com> wrote:

> On 3/14/2011 12:17 PM, Mike Snitzer wrote:
> >
> >>Is there any concern with mixing 4KB-sector drives with 512-byte
> >>sector drives in the same LV?
> >
> >Both LVM2 and Device Mapper have been updated to accommodate stacking
> >such a mix of drives.
> >
> >See this for a bit more detail:
> >http://people.redhat.com/msnitzer/docs/io-limits.txt
> >
> >Particularly, the "Stacking I/O Limits" section.
> >
> >The concern raised for partial (4k) writes to the 512b drive was
> >discussed a bit more here: http://lkml.org/lkml/2010/2/22/295
> 
> Are there any version-level hints about when/where these changes
> appear and come together in the real world (i.e. distributions like
> RHEL, debian, Ubuntu)?

For the kernel, the bulk of associated infrastructure (ata, scsi, block,
dm, md, etc) went in 2.6.31, 2.6.32 saw some improvements, and 2.6.33
and 2.6.34 saw a few bug fixes.

v2.6.32.11 saw a backport of the 2.6.33 and 2.6.34 bug fixes via commit
9b2ff97

RHEL6 has all this.  I cannot speak for debian and/or Ubuntu.

As for LVM2, you'd want >= 2.02.62.

Mike

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Ron Johnson]

On 03/14/2011 01:02 PM, Mike Snitzer wrote:
> On Mon, Mar 14 2011 at  1:32pm -0400,
> Les Mikesell<lesmikesell@gmail.com>  wrote:
>
>> On 3/14/2011 12:17 PM, Mike Snitzer wrote:
>>>
>>>> Is there any concern with mixing 4KB-sector drives with 512-byte
>>>> sector drives in the same LV?
>>>
>>> Both LVM2 and Device Mapper have been updated to accommodate stacking
>>> such a mix of drives.
>>>
>>> See this for a bit more detail:
>>> http://people.redhat.com/msnitzer/docs/io-limits.txt
>>>
>>> Particularly, the "Stacking I/O Limits" section.
>>>
>>> The concern raised for partial (4k) writes to the 512b drive was
>>> discussed a bit more here: http://lkml.org/lkml/2010/2/22/295
>>
>> Are there any version-level hints about when/where these changes
>> appear and come together in the real world (i.e. distributions like
>> RHEL, debian, Ubuntu)?
>
> For the kernel, the bulk of associated infrastructure (ata, scsi, block,
> dm, md, etc) went in 2.6.31, 2.6.32 saw some improvements, and 2.6.33
> and 2.6.34 saw a few bug fixes.
>
> v2.6.32.11 saw a backport of the 2.6.33 and 2.6.34 bug fixes via commit
> 9b2ff97
>
> RHEL6 has all this.  I cannot speak for debian and/or Ubuntu.
>
> As for LVM2, you'd want>= 2.02.62.
>

Thanks...

$ cat /etc/debian_version
wheezy/sid

$ /sbin/lvm version
   LVM version:     2.02.84(2) (2011-02-09)
   Library version: 1.02.63 (2011-02-09)

$ uname -r
2.6.37-2-amd64

-- 
I prefer banana-flavored energy bars made from tofu.

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Ron Johnson]

On 03/14/2011 12:17 PM, Mike Snitzer wrote:
> On Mon, Mar 14 2011 at 12:47pm -0400,
> Ron Johnson<ron.l.johnson@cox.net>  wrote:
>
>> Hi,
>>
>> Is there any concern with mixing 4KB-sector drives with 512-byte
>> sector drives in the same LV?
>
> Both LVM2 and Device Mapper have been updated to accommodate stacking
> such a mix of drives.
>
> See this for a bit more detail:
> http://people.redhat.com/msnitzer/docs/io-limits.txt
>
> Particularly, the "Stacking I/O Limits" section.
>
> The concern raised for partial (4k) writes to the 512b drive was
> discussed a bit more here: http://lkml.org/lkml/2010/2/22/295
>

Does this mean that util-linux v2.17.1 fdisk correctly handle AF 
disks?  (Note that I will *not* be booting off an AF device.)

ftp://ftp.kernel.org/pub/linux/utils/util-linux/v2.17/v2.17.1-ReleaseNotes

fdisk:
    - cleanup alignment, default to 1MiB offset  [Karel Zak]
    - don't check alignment_offset against geometry  [Karel Zak]
    - fallback for topology values  [Karel Zak]
    - fix ALIGN_UP  [Karel Zak]
    - fix check_alignment()  [Karel Zak]
    - fix default first sector  [Karel Zak]
    - use "optimal I/O size" in warnings  [Karel Zak]
    - use 1MiB offset and grain always when possible  [Karel Zak]
    - use more elegant way to count and check alignment  [Karel Zak]
    - use optimal_io_size  [Karel Zak]

-- 
I prefer banana-flavored energy bars made from tofu.

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Mike Snitzer]

On Mon, Mar 14 2011 at  3:13pm -0400,
Ron Johnson <ron.l.johnson@cox.net> wrote:

> On 03/14/2011 12:17 PM, Mike Snitzer wrote:
> >On Mon, Mar 14 2011 at 12:47pm -0400,
> >Ron Johnson<ron.l.johnson@cox.net>  wrote:
> >
> >>Hi,
> >>
> >>Is there any concern with mixing 4KB-sector drives with 512-byte
> >>sector drives in the same LV?
> >
> >Both LVM2 and Device Mapper have been updated to accommodate stacking
> >such a mix of drives.
> >
> >See this for a bit more detail:
> >http://people.redhat.com/msnitzer/docs/io-limits.txt
> >
> >Particularly, the "Stacking I/O Limits" section.
> >
> >The concern raised for partial (4k) writes to the 512b drive was
> >discussed a bit more here: http://lkml.org/lkml/2010/2/22/295
> >
> 
> Does this mean that util-linux v2.17.1 fdisk correctly handle AF
> disks?  (Note that I will *not* be booting off an AF device.)
> 
> ftp://ftp.kernel.org/pub/linux/utils/util-linux/v2.17/v2.17.1-ReleaseNotes
> 
> fdisk:
>    - cleanup alignment, default to 1MiB offset  [Karel Zak]
>    - don't check alignment_offset against geometry  [Karel Zak]
>    - fallback for topology values  [Karel Zak]
>    - fix ALIGN_UP  [Karel Zak]
>    - fix check_alignment()  [Karel Zak]
>    - fix default first sector  [Karel Zak]
>    - use "optimal I/O size" in warnings  [Karel Zak]
>    - use 1MiB offset and grain always when possible  [Karel Zak]
>    - use more elegant way to count and check alignment  [Karel Zak]
>    - use optimal_io_size  [Karel Zak]

Given that changelog, yes.

(cc'ing kzak for the authoritative answer ;)

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[John Drescher]

On Mon, Mar 14, 2011 at 3:13 PM, Ron Johnson <ron.l.johnson@cox.net> wrote:
> On 03/14/2011 12:17 PM, Mike Snitzer wrote:
>>
>> On Mon, Mar 14 2011 at 12:47pm -0400,
>> Ron Johnson<ron.l.johnson@cox.net> �wrote:
>>
>>> Hi,
>>>
>>> Is there any concern with mixing 4KB-sector drives with 512-byte
>>> sector drives in the same LV?
>>
>> Both LVM2 and Device Mapper have been updated to accommodate stacking
>> such a mix of drives.
>>
>> See this for a bit more detail:
>> http://people.redhat.com/msnitzer/docs/io-limits.txt
>>
>> Particularly, the "Stacking I/O Limits" section.
>>
>> The concern raised for partial (4k) writes to the 512b drive was
>> discussed a bit more here: http://lkml.org/lkml/2010/2/22/295
>>
>
> Does this mean that util-linux v2.17.1 fdisk correctly handle AF disks?
> �(Note that I will *not* be booting off an AF device.)
>
> ftp://ftp.kernel.org/pub/linux/utils/util-linux/v2.17/v2.17.1-ReleaseNotes
>
> fdisk:
> � - cleanup alignment, default to 1MiB offset �[Karel Zak]
> � - don't check alignment_offset against geometry �[Karel Zak]
> � - fallback for topology values �[Karel Zak]
> � - fix ALIGN_UP �[Karel Zak]
> � - fix check_alignment() �[Karel Zak]
> � - fix default first sector �[Karel Zak]
> � - use "optimal I/O size" in warnings �[Karel Zak]
> � - use 1MiB offset and grain always when possible �[Karel Zak]
> � - use more elegant way to count and check alignment �[Karel Zak]
> � - use optimal_io_size �[Karel Zak]
>
> --
> I prefer banana-flavored energy bars made from tofu.

fdisk now aligns partitions to sector 2048. I know this since it has
done that on the last few I formatted.

John

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Karel Zak]

On Mon, Mar 14, 2011 at 04:00:57PM -0400, Mike Snitzer wrote:
> On Mon, Mar 14 2011 at  3:13pm -0400,
> Ron Johnson <ron.l.johnson@cox.net> wrote:
> 
> > On 03/14/2011 12:17 PM, Mike Snitzer wrote:
> > >On Mon, Mar 14 2011 at 12:47pm -0400,
> > >Ron Johnson<ron.l.johnson@cox.net>  wrote:
> > >
> > >>Hi,
> > >>
> > >>Is there any concern with mixing 4KB-sector drives with 512-byte
> > >>sector drives in the same LV?
> > >
> > >Both LVM2 and Device Mapper have been updated to accommodate stacking
> > >such a mix of drives.
> > >
> > >See this for a bit more detail:
> > >http://people.redhat.com/msnitzer/docs/io-limits.txt
> > >
> > >Particularly, the "Stacking I/O Limits" section.
> > >
> > >The concern raised for partial (4k) writes to the 512b drive was
> > >discussed a bit more here: http://lkml.org/lkml/2010/2/22/295
> > >
> > 
> > Does this mean that util-linux v2.17.1 fdisk correctly handle AF
> > disks?  (Note that I will *not* be booting off an AF device.)

 ideally util-linux >= 2.17.2 (e.g. RHEL6)

> > 
> > ftp://ftp.kernel.org/pub/linux/utils/util-linux/v2.17/v2.17.1-ReleaseNotes
> > 
> > fdisk:
> >    - cleanup alignment, default to 1MiB offset  [Karel Zak]
> >    - don't check alignment_offset against geometry  [Karel Zak]
> >    - fallback for topology values  [Karel Zak]
> >    - fix ALIGN_UP  [Karel Zak]
> >    - fix check_alignment()  [Karel Zak]
> >    - fix default first sector  [Karel Zak]
> >    - use "optimal I/O size" in warnings  [Karel Zak]
> >    - use 1MiB offset and grain always when possible  [Karel Zak]
> >    - use more elegant way to count and check alignment  [Karel Zak]
> >    - use optimal_io_size  [Karel Zak]
> 
> Given that changelog, yes.

 Yes, it works. Note that you have to disable (-c -u) DOS compatible
 mode. The mode is disabled by default in Fedora, but enabled in RHEL6.

 Some hints:
 http://karelzak.blogspot.com/2010/05/4096-byte-sector-hard-drives.html

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Stuart D. Gathman]

On Tue, 15 Mar 2011, Karel Zak wrote:

> Some hints:
> http://karelzak.blogspot.com/2010/05/4096-byte-sector-hard-drives.html

I remember working with 256 byte sector hard drives the size of 
a mini refrigerator.  512 byte sectors were "advanced format".

--
 	      Stuart D. Gathman <stuart@bmsi.com>
     Business Management Systems Inc.  Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flammis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Stuart D. Gathman]

On Tue, 15 Mar 2011, Stuart D. Gathman wrote:

> On Tue, 15 Mar 2011, Karel Zak wrote:
>
>> Some hints:
>> http://karelzak.blogspot.com/2010/05/4096-byte-sector-hard-drives.html
>
> I remember working with 256 byte sector hard drives the size of a mini 
> refrigerator.  512 byte sectors were "advanced format".

More future oriented: I read about high density storage just around the
corner that uses much larger sectors, typically 128K or 256K.  These
are things like holographic memory.  The researchers complain that 
existing filesystems can't handle the large sector size efficiently.  (Don't
know what filesystems they tried.)  I note the similarity between
those sector sizes and flash erase blocks.

--
 	      Stuart D. Gathman <stuart@bmsi.com>
     Business Management Systems Inc.  Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flammis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Phillip Susi]

On 3/14/2011 1:17 PM, Mike Snitzer wrote:
> Both LVM2 and Device Mapper have been updated to accommodate stacking
> such a mix of drives.
> 
> See this for a bit more detail:
> http://people.redhat.com/msnitzer/docs/io-limits.txt
> 
> Particularly, the "Stacking I/O Limits" section.
> 
> The concern raised for partial (4k) writes to the 512b drive was
> discussed a bit more here: http://lkml.org/lkml/2010/2/22/295

Unfortunately this does not help with the WD EARS model drives ( are
there any other 4kb sector drives on the market now? ), since they lie
and report that they have 512 byte sectors.

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Mike Snitzer]

On Wed, Mar 16 2011 at  4:45pm -0400,
Phillip Susi <psusi@cfl.rr.com> wrote:

> On 3/14/2011 1:17 PM, Mike Snitzer wrote:
> > Both LVM2 and Device Mapper have been updated to accommodate stacking
> > such a mix of drives.
> > 
> > See this for a bit more detail:
> > http://people.redhat.com/msnitzer/docs/io-limits.txt
> > 
> > Particularly, the "Stacking I/O Limits" section.
> > 
> > The concern raised for partial (4k) writes to the 512b drive was
> > discussed a bit more here: http://lkml.org/lkml/2010/2/22/295
> 
> Unfortunately this does not help with the WD EARS model drives ( are
> there any other 4kb sector drives on the market now? ), since they lie
> and report that they have 512 byte sectors.

I'm not following what you're saying.  The kernel's blk_stack_limits()
infrastructure accounts for "desktop" class 4K devices too (4K physical,
512b logical) -- as does DM and lvm2.

If given:

"desktop" class drive:
physical_block_size=4096
logical_block_size=512
minimum_io_size=4096
optimal_io_size=0

conventional 512 drive:
physical_block_size=512
logical_block_size=512
minimum_io_size=512
optimal_io_size=0

Stacking these drives would result in a logical device that has:

physical_block_size=4096
logical_block_size=512
minimum_io_size=4096
optimal_io_size=0

And yes, there are native 4K "enterprise" class drives (4K physical, 4K
logical) in the market.

Mike

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Les Mikesell]

On 3/16/2011 5:55 PM, Mike Snitzer wrote:
>
>> On 3/14/2011 1:17 PM, Mike Snitzer wrote:
>>> Both LVM2 and Device Mapper have been updated to accommodate stacking
>>> such a mix of drives.
>>>
>>> See this for a bit more detail:
>>> http://people.redhat.com/msnitzer/docs/io-limits.txt
>>>
>>> Particularly, the "Stacking I/O Limits" section.
>>>
>>> The concern raised for partial (4k) writes to the 512b drive was
>>> discussed a bit more here: http://lkml.org/lkml/2010/2/22/295
>>
>> Unfortunately this does not help with the WD EARS model drives ( are
>> there any other 4kb sector drives on the market now? ), since they lie
>> and report that they have 512 byte sectors.
>
> I'm not following what you're saying.  The kernel's blk_stack_limits()
> infrastructure accounts for "desktop" class 4K devices too (4K physical,
> 512b logical) -- as does DM and lvm2.
>
> If given:
>
> "desktop" class drive:
> physical_block_size=4096
> logical_block_size=512
> minimum_io_size=4096
> optimal_io_size=0

How does the kernel know about the physical_block_size when the device 
reports itself as 512?  And they handle 512 byte writes, just very slowly.

-- 
   Les Mikesell
    lesmikesell@gmail.com

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Mike Snitzer]

On Wed, Mar 16 2011 at  7:11pm -0400,
Les Mikesell <lesmikesell@gmail.com> wrote:

> On 3/16/2011 5:55 PM, Mike Snitzer wrote:
> >
> >>On 3/14/2011 1:17 PM, Mike Snitzer wrote:
> >>>Both LVM2 and Device Mapper have been updated to accommodate stacking
> >>>such a mix of drives.
> >>>
> >>>See this for a bit more detail:
> >>>http://people.redhat.com/msnitzer/docs/io-limits.txt
> >>>
> >>>Particularly, the "Stacking I/O Limits" section.
> >>>
> >>>The concern raised for partial (4k) writes to the 512b drive was
> >>>discussed a bit more here: http://lkml.org/lkml/2010/2/22/295
> >>
> >>Unfortunately this does not help with the WD EARS model drives ( are
> >>there any other 4kb sector drives on the market now? ), since they lie
> >>and report that they have 512 byte sectors.
> >
> >I'm not following what you're saying.  The kernel's blk_stack_limits()
> >infrastructure accounts for "desktop" class 4K devices too (4K physical,
> >512b logical) -- as does DM and lvm2.
> >
> >If given:
> >
> >"desktop" class drive:
> >physical_block_size=4096
> >logical_block_size=512
> >minimum_io_size=4096
> >optimal_io_size=0
> 
> How does the kernel know about the physical_block_size when the
> device reports itself as 512?  And they handle 512 byte writes, just
> very slowly.

The drive exports the information as part of its response to the
IDENTIFY DEVICE (for ATA) or READ CAPACITY (for SCSI) command -- it
splits out the physical and logical block sizes along with other
attributes.  The kernel's SCSI (and libata) layer issues these commands
to the drive.

Much more detail available in Martin's paper:
http://oss.oracle.com/~mkp/docs/linux-advanced-storage.pdf

Mike

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Phillip Susi]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 03/16/2011 06:55 PM, Mike Snitzer wrote:
> I'm not following what you're saying.  The kernel's blk_stack_limits()
> infrastructure accounts for "desktop" class 4K devices too (4K physical,
> 512b logical) -- as does DM and lvm2.

The kernel has the ability to read it from the drive and report it to
the user space tools, which have been patched to use it, but the WD EARS
drives lie and claim 512/512 instead of 512/4096.
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Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Mike Snitzer]

On Wed, Mar 16 2011 at  8:02pm -0400,
Mike Snitzer <snitzer@redhat.com> wrote:

> On Wed, Mar 16 2011 at  7:11pm -0400,
> Les Mikesell <lesmikesell@gmail.com> wrote:
> 
> > On 3/16/2011 5:55 PM, Mike Snitzer wrote:
> > >
> > >>On 3/14/2011 1:17 PM, Mike Snitzer wrote:
> > >>>Both LVM2 and Device Mapper have been updated to accommodate stacking
> > >>>such a mix of drives.
> > >>>
> > >>>See this for a bit more detail:
> > >>>http://people.redhat.com/msnitzer/docs/io-limits.txt
> > >>>
> > >>>Particularly, the "Stacking I/O Limits" section.
> > >>>
> > >>>The concern raised for partial (4k) writes to the 512b drive was
> > >>>discussed a bit more here: http://lkml.org/lkml/2010/2/22/295
> > >>
> > >>Unfortunately this does not help with the WD EARS model drives ( are
> > >>there any other 4kb sector drives on the market now? ), since they lie
> > >>and report that they have 512 byte sectors.
> > >
> > >I'm not following what you're saying.  The kernel's blk_stack_limits()
> > >infrastructure accounts for "desktop" class 4K devices too (4K physical,
> > >512b logical) -- as does DM and lvm2.
> > >
> > >If given:
> > >
> > >"desktop" class drive:
> > >physical_block_size=4096
> > >logical_block_size=512
> > >minimum_io_size=4096
> > >optimal_io_size=0
> > 
> > How does the kernel know about the physical_block_size when the
> > device reports itself as 512?  And they handle 512 byte writes, just
> > very slowly.
> 
> The drive exports the information as part of its response to the
> IDENTIFY DEVICE (for ATA) or READ CAPACITY (for SCSI) command -- it
> splits out the physical and logical block sizes along with other
> attributes.  The kernel's SCSI (and libata) layer issues these commands
> to the drive.

I just got Phillips' mail that the drive lies and reports 512/512.
(and I read your mail too quickly).

So yeah, the WD EARS drives are scary.  Best for WD to defend or explain
them.

Mike

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Martin K. Petersen]

>>>>> "Phillip" == Phillip Susi <psusi@cfl.rr.com> writes:

Phillip> The kernel has the ability to read it from the drive and report
Phillip> it to the user space tools, which have been patched to use it,
Phillip> but the WD EARS drives lie and claim 512/512 instead of
Phillip> 512/4096.

The saving grace is that modern util-linux/dm tooling aligns on 1MB by
default instead of sector 63.

And yes, there are Advanced Format drives shipping from both Hitachi and
Seagate...

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[hansbkk]

On Thu, Mar 17, 2011 at 7:39 AM, Martin K. Petersen
<martin.petersen@oracle.com> wrote:
> And yes, there are Advanced Format drives shipping from both Hitachi and
> Seagate...

And Samsung

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Ron Johnson]

On 03/16/2011 07:39 PM, Martin K. Petersen wrote:
>>>>>> "Phillip" == Phillip Susi<psusi@cfl.rr.com>  writes:
>
> Phillip>  The kernel has the ability to read it from the drive and report
> Phillip>  it to the user space tools, which have been patched to use it,
> Phillip>  but the WD EARS drives lie and claim 512/512 instead of
> Phillip>  512/4096.
>
> The saving grace is that modern util-linux/dm tooling aligns on 1MB by
> default instead of sector 63.
>

So, given the correct options ( -c -b 4096 ), v2.17.2 will handle 
the 2TB WD Caviar Green WD20EARS drives which I just bought for my 
external backup device...  Right?

(Along with a current lvm and kernel.)
https://www.redhat.com/archives/linux-lvm/2011-March/msg00053.html

-- 
I prefer banana-flavored energy bars made from tofu.

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Karel Zak]

On Thu, Mar 17, 2011 at 06:47:18PM -0500, Ron Johnson wrote:
> On 03/16/2011 07:39 PM, Martin K. Petersen wrote:
>>>>>>> "Phillip" == Phillip Susi<psusi@cfl.rr.com>  writes:
>>
>> Phillip>  The kernel has the ability to read it from the drive and report
>> Phillip>  it to the user space tools, which have been patched to use it,
>> Phillip>  but the WD EARS drives lie and claim 512/512 instead of
>> Phillip>  512/4096.
>>
>> The saving grace is that modern util-linux/dm tooling aligns on 1MB by
>> default instead of sector 63.
>>
>
> So, given the correct options ( -c -b 4096 ), v2.17.2 will handle the 2TB 
> WD Caviar Green WD20EARS drives which I just bought for my external 
> backup device...  Right?

The -b option is usually unnecessary (for v2.17 is the -c enough).

It seems (according to feedback from users) that newer WDxxEARS disks
are already fixed. 
http://community.wdc.com/t5/Desktop/Problem-with-WD-Advanced-Format-drive-in-LINUX-WD15EARS/m-p/20675#M1245


Try

  hdparm -I /dev/<disk>

to see more details, for example:

    Logical  Sector size:                   512 bytes
    Physical Sector size:                  4096 bytes

and
 
   # cat /sys/block/<disk>/queue/physical_block_size
   4096


It's also better to update to util-linux v2.18 or v2.19 where all the
new features are enabled by default (so -c is unnecessary too).

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: [linux-lvm] Advanced Format disks mixed with regular disks?

[Les Mikesell]

On 3/22/2011 5:23 AM, Karel Zak wrote:
>
> It seems (according to feedback from users) that newer WDxxEARS disks
> are already fixed.
> http://community.wdc.com/t5/Desktop/Problem-with-WD-Advanced-Format-drive-in-LINUX-WD15EARS/m-p/20675#M1245
>
>
> Try
>
>    hdparm -I /dev/<disk>
>
> to see more details, for example:
>
>      Logical  Sector size:                   512 bytes
>      Physical Sector size:                  4096 bytes
>
> and
>
>     # cat /sys/block/<disk>/queue/physical_block_size
>     4096

This isn't exactly an LVM issue (but I suppose it could be, and at least 
some people understand the problem here...).  I'd like to do RAID1 with 
a WD 'Scorpio' laptop-size 750 gig drive which has 4k sectors but 
reports 512 as both the physical and logical size as one member with a 
full size Seagate with a matching number of sectors as the other.  And 
I'd like to periodically swap the small drive, rotate offsite, and 
resync a different one.   As things stand, it would take days for this 
sync to complete so I've been using full size drives for both instances. 
   Is there some hope of getting the sync time down to 8 hours or so? 
And is that going to involve both updating to a fairly recent Linux 
distro (it's Centos 5.x now) and starting from scratch with new 
partition alignment?

For full disclosure, this is a backuppc archive with a bizallion 
hardlinks that would take many days to copy with a file-oriented 
approach and it's really a 3-member raid1 where 2 drives are always 
present and one swapped in long enough to resync.  But those things 
shouldn't matter except for the difficulty in changing the partition 
alignment.  The existing one runs to the end of the disk so I can't 
offset the start and still match up in size.

-- 
   Les Mikesell
    lesmikesell@gmail.com