| Author |
Message |
Rui J.M. Silva
Guest
|
 Posted:
Tue Nov 23, 2004 10:51 pm Post subject:
Using Diskpar (without the "t") |
|
|
I recenly attended MS IT Forum and there were a lot of recomendations to use
diskpar to align disk tracks.
There's not much documentation about this tool, so I have a couple of
questions:
1) Will I gain performance if my disk has 63 sectors/track? Because I don't
see how to match 4096 kB allocation units into 63 sectors/track...
2) My disk has 512 bytes/sector, so the correct offset would be 32768 bytes
(64 tracks), right?
3) Where can I find more documentation about diskpar?
thanks.
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Scott Schnoll [MSFT]
Guest
|
| Posted:
Tue Nov 23, 2004 11:24 pm Post subject:
Re: Using Diskpar (without the "t") |
|
|
Hi,
I mentioned this in both my IT Forum sessions. :-)
Diskpar (Disk Alignment Tool) is a tool that can be found in the Windows
2000 Server Resource Kit. The documentation for Diskpar can be found in the
Windows 2000 Resource Kit Tools Help file.
DiskPar is a command-line tool that finds and modifies the starting sector
on a disk to improve disk performance. It is only used with multi-disk
systems.
Windows has an internal structure called the Master Boot Record (MBR) that
limits the maximum default hidden sectors to 63. For this reason, the
default starting sector for disks that report more than 63 sectors/track is
the 64th sector. For disks with 64 or more sectors/track this can cause
misalignment when data is transferred to and from the disks. For example,
with a disk that has 64 sectors/track, what appear to be track aligned
transfers begin at the last sector of one track and span to the next track.
The following issues further complicate this problem:
a.. The track information reported by disks doesn't always reflect reality
b.. Many disks have different numbers of sectors on different tracks (for
example: outer vs. inner bands)
c.. Basic Block Microsoft® MS-DOS® interoperability issues with Microsoft®
Windows® 95 and Microsoft® Windows® 98 restrict changes to partition
alignment
To get maximum disk performance on Windows for disks which have alignment
optimizations and large track sizes, you can use DiskPar to obtain and set
partition information. By doing so, you can significantly improve disk
activity performance for some specialized controllers.
Switches for Diskpar are shown when using the -? option:
C:\WINDOWS>diskpar /?
Usage: diskpar [ -i | -s ] DriveNumber
-i: query drive layout and partition information
-s: set partition information (only used on raw drive please)
Here is some example information:
a.. You have a disk controller that can only do lazy writes if the writes
are within 4 kilobyte (KB) boundaries.
b.. One of the disks you are using reports it supports more than 63
sectors per track. You can discover this information by using diskpar -i or
any other tool, such as DMDiag which displays starting sector information.
c.. You also have an application which continuously causes 64 KB writes to
disk. In this case, each write will not be within the 4 KB boundary and disk
performance would be poor.
Using DiskPar, you can modify the hidden starting offset to significantly
improve write performance. Here is an example that demonstrates how to do
this:
1.. Start Disk Management on disk 0.
2.. Delete all partitions on disk 1 making it a raw drive. Backup any data
you don't want to lose before removing partitions.
3.. From disk 0, run DiskPar to set the starting offset and create the
first partition on disk 1:
diskpar -s 1 4.. Enter the new starting offset (in sectors), and the
partition length (in MB). This writes the new starting sector information to
the Master Boot Record (MBR) for that disk, and creates the first partition.
5.. Using Disk Manager, create and format all other desired partitions on
disk 1.
Before using DiskPar, I recommend that you check with your hardware vendor
to see if they have specific guidance for their storage solution when
running Exchange.
Feel free to post back here with any follow-up questions you might have. I
hope this helps!
--
Scott Schnoll
This posting is provided "AS IS" with no warranties, and confers no
rights. Please do not send email directly to this alias. This alias is for
newsgroup
purposes only.
"Rui J.M. Silva" <Rui J.M. Silva@discussions.microsoft.com> wrote in message
news:170EC0F2-2E13-4A1D-AB66-DDC409E53851@microsoft.com...
| Quote: | I recenly attended MS IT Forum and there were a lot of recomendations to
use
diskpar to align disk tracks.
There's not much documentation about this tool, so I have a couple of
questions:
1) Will I gain performance if my disk has 63 sectors/track? Because I
don't
see how to match 4096 kB allocation units into 63 sectors/track...
2) My disk has 512 bytes/sector, so the correct offset would be 32768
bytes
(64 tracks), right?
3) Where can I find more documentation about diskpar?
thanks. |
|
|
| Back to top |
|
|
Rui J.M. Silva
Guest
|
| Posted:
Tue Nov 23, 2004 11:53 pm Post subject:
Re: Using Diskpar (without the "t") |
|
|
Thank you Scott for all the usefull information.
I was at your session about best practices for cluster deployment and, let
me tell you, it was a great session.
Back to my issue, I already did some testing with diskpar. When I run it
with the -i switch I get the following information:
C:\>diskpar -i 1
---- Drive 1 Geometry Infomation ----
Cylinders = 7834
TracksPerCylinder = 255
SectorsPerTrack = 63
BytesPerSector = 512
DiskSize = 64436843520 (Bytes) = 61451 (MB)
Since this tool reports 63 sectors/track, there's no point in using Diskpar,
right?
"Scott Schnoll [MSFT]" wrote:
| Quote: | Hi,
I mentioned this in both my IT Forum sessions. :-)
Diskpar (Disk Alignment Tool) is a tool that can be found in the Windows
2000 Server Resource Kit. The documentation for Diskpar can be found in the
Windows 2000 Resource Kit Tools Help file.
DiskPar is a command-line tool that finds and modifies the starting sector
on a disk to improve disk performance. It is only used with multi-disk
systems.
Windows has an internal structure called the Master Boot Record (MBR) that
limits the maximum default hidden sectors to 63. For this reason, the
default starting sector for disks that report more than 63 sectors/track is
the 64th sector. For disks with 64 or more sectors/track this can cause
misalignment when data is transferred to and from the disks. For example,
with a disk that has 64 sectors/track, what appear to be track aligned
transfers begin at the last sector of one track and span to the next track.
The following issues further complicate this problem:
a.. The track information reported by disks doesn't always reflect reality
b.. Many disks have different numbers of sectors on different tracks (for
example: outer vs. inner bands)
c.. Basic Block Microsoft® MS-DOS® interoperability issues with Microsoft®
Windows® 95 and Microsoft® Windows® 98 restrict changes to partition
alignment
To get maximum disk performance on Windows for disks which have alignment
optimizations and large track sizes, you can use DiskPar to obtain and set
partition information. By doing so, you can significantly improve disk
activity performance for some specialized controllers.
Switches for Diskpar are shown when using the -? option:
C:\WINDOWS>diskpar /?
Usage: diskpar [ -i | -s ] DriveNumber
-i: query drive layout and partition information
-s: set partition information (only used on raw drive please)
Here is some example information:
a.. You have a disk controller that can only do lazy writes if the writes
are within 4 kilobyte (KB) boundaries.
b.. One of the disks you are using reports it supports more than 63
sectors per track. You can discover this information by using diskpar -i or
any other tool, such as DMDiag which displays starting sector information.
c.. You also have an application which continuously causes 64 KB writes to
disk. In this case, each write will not be within the 4 KB boundary and disk
performance would be poor.
Using DiskPar, you can modify the hidden starting offset to significantly
improve write performance. Here is an example that demonstrates how to do
this:
1.. Start Disk Management on disk 0.
2.. Delete all partitions on disk 1 making it a raw drive. Backup any data
you don't want to lose before removing partitions.
3.. From disk 0, run DiskPar to set the starting offset and create the
first partition on disk 1:
diskpar -s 1 4.. Enter the new starting offset (in sectors), and the
partition length (in MB). This writes the new starting sector information to
the Master Boot Record (MBR) for that disk, and creates the first partition.
5.. Using Disk Manager, create and format all other desired partitions on
disk 1.
Before using DiskPar, I recommend that you check with your hardware vendor
to see if they have specific guidance for their storage solution when
running Exchange.
Feel free to post back here with any follow-up questions you might have. I
hope this helps!
--
Scott Schnoll
This posting is provided "AS IS" with no warranties, and confers no
rights. Please do not send email directly to this alias. This alias is for
newsgroup
purposes only.
"Rui J.M. Silva" <Rui J.M. Silva@discussions.microsoft.com> wrote in message
news:170EC0F2-2E13-4A1D-AB66-DDC409E53851@microsoft.com...
I recenly attended MS IT Forum and there were a lot of recomendations to
use
diskpar to align disk tracks.
There's not much documentation about this tool, so I have a couple of
questions:
1) Will I gain performance if my disk has 63 sectors/track? Because I
don't
see how to match 4096 kB allocation units into 63 sectors/track...
2) My disk has 512 bytes/sector, so the correct offset would be 32768
bytes
(64 tracks), right?
3) Where can I find more documentation about diskpar?
thanks.
|
|
|
| Back to top |
|
|
Scott Schnoll [MSFT]
Guest
|
| Posted:
Wed Nov 24, 2004 12:05 am Post subject:
Re: Using Diskpar (without the "t") |
|
|
Thanks very much for the kind words. I'm very pleased you enjoyed the
session.
In your case, I don't believe Diskpar will help here. Sector alignment is
only needed for some storage enclosures. However, to be 100% sure on this,
please check with your hardware vendor to see if you will experience any
benefits from using it. The key here is to make sure that you are not
crossing sector boundaries on writes, as that reduces performance.
--
Scott Schnoll
This posting is provided "AS IS" with no warranties, and confers no
rights. Please do not send email directly to this alias. This alias is for
newsgroup
purposes only.
"Rui J.M. Silva" <rjms(nospam4me)@oninet.pt> wrote in message
news:257B24A7-C918-42B7-AE6C-E115A3F19537@microsoft.com...
| Quote: | Thank you Scott for all the usefull information.
I was at your session about best practices for cluster deployment and, let
me tell you, it was a great session.
Back to my issue, I already did some testing with diskpar. When I run it
with the -i switch I get the following information:
C:\>diskpar -i 1
---- Drive 1 Geometry Infomation ----
Cylinders = 7834
TracksPerCylinder = 255
SectorsPerTrack = 63
BytesPerSector = 512
DiskSize = 64436843520 (Bytes) = 61451 (MB)
Since this tool reports 63 sectors/track, there's no point in using
Diskpar,
right?
"Scott Schnoll [MSFT]" wrote:
Hi,
I mentioned this in both my IT Forum sessions. :-)
Diskpar (Disk Alignment Tool) is a tool that can be found in the Windows
2000 Server Resource Kit. The documentation for Diskpar can be found in
the
Windows 2000 Resource Kit Tools Help file.
DiskPar is a command-line tool that finds and modifies the starting
sector
on a disk to improve disk performance. It is only used with multi-disk
systems.
Windows has an internal structure called the Master Boot Record (MBR)
that
limits the maximum default hidden sectors to 63. For this reason, the
default starting sector for disks that report more than 63 sectors/track
is
the 64th sector. For disks with 64 or more sectors/track this can cause
misalignment when data is transferred to and from the disks. For example,
with a disk that has 64 sectors/track, what appear to be track aligned
transfers begin at the last sector of one track and span to the next
track.
The following issues further complicate this problem:
a.. The track information reported by disks doesn't always reflect
reality
b.. Many disks have different numbers of sectors on different tracks
(for
example: outer vs. inner bands)
c.. Basic Block Microsoft® MS-DOS® interoperability issues with
Microsoft®
Windows® 95 and Microsoft® Windows® 98 restrict changes to partition
alignment
To get maximum disk performance on Windows for disks which have alignment
optimizations and large track sizes, you can use DiskPar to obtain and
set
partition information. By doing so, you can significantly improve disk
activity performance for some specialized controllers.
Switches for Diskpar are shown when using the -? option:
C:\WINDOWS>diskpar /?
Usage: diskpar [ -i | -s ] DriveNumber
-i: query drive layout and partition information
-s: set partition information (only used on raw drive please)
Here is some example information:
a.. You have a disk controller that can only do lazy writes if the
writes
are within 4 kilobyte (KB) boundaries.
b.. One of the disks you are using reports it supports more than 63
sectors per track. You can discover this information by using diskpar -i
or
any other tool, such as DMDiag which displays starting sector
information.
c.. You also have an application which continuously causes 64 KB writes
to
disk. In this case, each write will not be within the 4 KB boundary and
disk
performance would be poor.
Using DiskPar, you can modify the hidden starting offset to significantly
improve write performance. Here is an example that demonstrates how to do
this:
1.. Start Disk Management on disk 0.
2.. Delete all partitions on disk 1 making it a raw drive. Backup any
data
you don't want to lose before removing partitions.
3.. From disk 0, run DiskPar to set the starting offset and create the
first partition on disk 1:
diskpar -s 1 4.. Enter the new starting offset (in sectors), and the
partition length (in MB). This writes the new starting sector information
to
the Master Boot Record (MBR) for that disk, and creates the first
partition.
5.. Using Disk Manager, create and format all other desired partitions
on
disk 1.
Before using DiskPar, I recommend that you check with your hardware
vendor
to see if they have specific guidance for their storage solution when
running Exchange.
Feel free to post back here with any follow-up questions you might have.
I
hope this helps!
--
Scott Schnoll
This posting is provided "AS IS" with no warranties, and confers no
rights. Please do not send email directly to this alias. This alias is
for
newsgroup
purposes only.
"Rui J.M. Silva" <Rui J.M. Silva@discussions.microsoft.com> wrote in
message
news:170EC0F2-2E13-4A1D-AB66-DDC409E53851@microsoft.com...
I recenly attended MS IT Forum and there were a lot of recomendations to
use
diskpar to align disk tracks.
There's not much documentation about this tool, so I have a couple of
questions:
1) Will I gain performance if my disk has 63 sectors/track? Because I
don't
see how to match 4096 kB allocation units into 63 sectors/track...
2) My disk has 512 bytes/sector, so the correct offset would be 32768
bytes
(64 tracks), right?
3) Where can I find more documentation about diskpar?
thanks.
|
|
|
| Back to top |
|
|
Rui J.M. Silva
Guest
|
| Posted:
Wed Nov 24, 2004 12:17 am Post subject:
Re: Using Diskpar (without the "t") |
|
|
OK, thanks.
I'll check with the HW vendor. If I find anything new I'll let you know.
"Scott Schnoll [MSFT]" wrote:
| Quote: | Thanks very much for the kind words. I'm very pleased you enjoyed the
session.
In your case, I don't believe Diskpar will help here. Sector alignment is
only needed for some storage enclosures. However, to be 100% sure on this,
please check with your hardware vendor to see if you will experience any
benefits from using it. The key here is to make sure that you are not
crossing sector boundaries on writes, as that reduces performance.
--
Scott Schnoll
This posting is provided "AS IS" with no warranties, and confers no
rights. Please do not send email directly to this alias. This alias is for
newsgroup
purposes only.
"Rui J.M. Silva" <rjms(nospam4me)@oninet.pt> wrote in message
news:257B24A7-C918-42B7-AE6C-E115A3F19537@microsoft.com...
Thank you Scott for all the usefull information.
I was at your session about best practices for cluster deployment and, let
me tell you, it was a great session.
Back to my issue, I already did some testing with diskpar. When I run it
with the -i switch I get the following information:
C:\>diskpar -i 1
---- Drive 1 Geometry Infomation ----
Cylinders = 7834
TracksPerCylinder = 255
SectorsPerTrack = 63
BytesPerSector = 512
DiskSize = 64436843520 (Bytes) = 61451 (MB)
Since this tool reports 63 sectors/track, there's no point in using
Diskpar,
right?
"Scott Schnoll [MSFT]" wrote:
Hi,
I mentioned this in both my IT Forum sessions. :-)
Diskpar (Disk Alignment Tool) is a tool that can be found in the Windows
2000 Server Resource Kit. The documentation for Diskpar can be found in
the
Windows 2000 Resource Kit Tools Help file.
DiskPar is a command-line tool that finds and modifies the starting
sector
on a disk to improve disk performance. It is only used with multi-disk
systems.
Windows has an internal structure called the Master Boot Record (MBR)
that
limits the maximum default hidden sectors to 63. For this reason, the
default starting sector for disks that report more than 63 sectors/track
is
the 64th sector. For disks with 64 or more sectors/track this can cause
misalignment when data is transferred to and from the disks. For example,
with a disk that has 64 sectors/track, what appear to be track aligned
transfers begin at the last sector of one track and span to the next
track.
The following issues further complicate this problem:
a.. The track information reported by disks doesn't always reflect
reality
b.. Many disks have different numbers of sectors on different tracks
(for
example: outer vs. inner bands)
c.. Basic Block Microsoft® MS-DOS® interoperability issues with
Microsoft®
Windows® 95 and Microsoft® Windows® 98 restrict changes to partition
alignment
To get maximum disk performance on Windows for disks which have alignment
optimizations and large track sizes, you can use DiskPar to obtain and
set
partition information. By doing so, you can significantly improve disk
activity performance for some specialized controllers.
Switches for Diskpar are shown when using the -? option:
C:\WINDOWS>diskpar /?
Usage: diskpar [ -i | -s ] DriveNumber
-i: query drive layout and partition information
-s: set partition information (only used on raw drive please)
Here is some example information:
a.. You have a disk controller that can only do lazy writes if the
writes
are within 4 kilobyte (KB) boundaries.
b.. One of the disks you are using reports it supports more than 63
sectors per track. You can discover this information by using diskpar -i
or
any other tool, such as DMDiag which displays starting sector
information.
c.. You also have an application which continuously causes 64 KB writes
to
disk. In this case, each write will not be within the 4 KB boundary and
disk
performance would be poor.
Using DiskPar, you can modify the hidden starting offset to significantly
improve write performance. Here is an example that demonstrates how to do
this:
1.. Start Disk Management on disk 0.
2.. Delete all partitions on disk 1 making it a raw drive. Backup any
data
you don't want to lose before removing partitions.
3.. From disk 0, run DiskPar to set the starting offset and create the
first partition on disk 1:
diskpar -s 1 4.. Enter the new starting offset (in sectors), and the
partition length (in MB). This writes the new starting sector information
to
the Master Boot Record (MBR) for that disk, and creates the first
partition.
5.. Using Disk Manager, create and format all other desired partitions
on
disk 1.
Before using DiskPar, I recommend that you check with your hardware
vendor
to see if they have specific guidance for their storage solution when
running Exchange.
Feel free to post back here with any follow-up questions you might have.
I
hope this helps!
--
Scott Schnoll
This posting is provided "AS IS" with no warranties, and confers no
rights. Please do not send email directly to this alias. This alias is
for
newsgroup
purposes only.
"Rui J.M. Silva" <Rui J.M. Silva@discussions.microsoft.com> wrote in
message
news:170EC0F2-2E13-4A1D-AB66-DDC409E53851@microsoft.com...
I recenly attended MS IT Forum and there were a lot of recomendations to
use
diskpar to align disk tracks.
There's not much documentation about this tool, so I have a couple of
questions:
1) Will I gain performance if my disk has 63 sectors/track? Because I
don't
see how to match 4096 kB allocation units into 63 sectors/track...
2) My disk has 512 bytes/sector, so the correct offset would be 32768
bytes
(64 tracks), right?
3) Where can I find more documentation about diskpar?
thanks.
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