disk sector alignment

Wher can i read more about disk sector alignment that helps speed IO for
SQL.
Or can someone just explain it in lay man terms? Why do we need it ? How do
do it and also how can we confirm its done ?
On older HP storage, I found about a 10% gain with SQLIO testing sequential
writes to simulate tlog activity. The best setting I found was 128 offset
and 64k NT allocation unit. However, I would test for the optimal settings
for the drive based on the type of IO you expect and what the vendor
recommends. I have see HP recommend both a 64 and 128 offset depending on
where you look.
This blog can give you some info on the type of IO a data drive, log or
backup drive would have as well as info on SQLIO.
http://blogs.msdn.com/sqlcat/archive/2005/11/17/493944.aspx
Look up the help on diskpart.exe as well.
HTH
Jason Massie
Web: http://statisticsio.com
RSS: http://feeds.feedburner.com/statisticsio
"Hassan" <hassan@.hotmail.com> wrote in message
news:erUAWMpPIHA.2000@.TK2MSFTNGP05.phx.gbl...
> Wher can i read more about disk sector alignment that helps speed IO for
> SQL.
> Or can someone just explain it in lay man terms? Why do we need it ? How
> do do it and also how can we confirm its done ?
>
|||Hassan,
This is pretty good:
http://sqlblogcasts.com/blogs/christian/archive/2007/10/09/disk-sector-alignment.aspx
RLF
"Hassan" <hassan@.hotmail.com> wrote in message
news:erUAWMpPIHA.2000@.TK2MSFTNGP05.phx.gbl...
> Wher can i read more about disk sector alignment that helps speed IO for
> SQL.
> Or can someone just explain it in lay man terms? Why do we need it ? How
> do do it and also how can we confirm its done ?
>
|||use diskpart to see information about alignment and also to create volumes
that are aligned
search the web for SQL Server Predeployment I/O Best Practices for a great
document.
search microsoft.com for diskpart for documentation on that tool
in a nut shell, un-aligned sectors can result in 2 physical I/Os for a
single I/O request because of the way partitions are laid down on the disk
structure. 2-for-1 is obviously a bad thing for performance.
Kevin G. Boles
TheSQLGuru
Indicium Resources, Inc.
kgboles a earthlink dt net
"Hassan" <hassan@.hotmail.com> wrote in message
news:erUAWMpPIHA.2000@.TK2MSFTNGP05.phx.gbl...
> Wher can i read more about disk sector alignment that helps speed IO for
> SQL.
> Or can someone just explain it in lay man terms? Why do we need it ? How
> do do it and also how can we confirm its done ?
>
|||Also take a look here:
http://sqlblog.com/blogs/linchi_shea/archive/2007/02/01/performance-impact-of-disk-misalignment.aspx
and
http://sqlblog.com/blogs/linchi_shea/archive/2007/07/19/disk-partition-alignment-in-the-published-tpc-benchmarks.aspx
Linchi
"Hassan" wrote:

> Wher can i read more about disk sector alignment that helps speed IO for
> SQL.
> Or can someone just explain it in lay man terms? Why do we need it ? How do
> do it and also how can we confirm its done ?
>
>