Re: % Disk Time (Perfmon)
From: Uri Dimant (urid_at_iscar.co.il)
Date: 08/04/04
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Date: Wed, 4 Aug 2004 16:06:05 +0200
Brian
First of all i have said 'probably'
Secondly if you have this counter higher than 55% for continuous periods
(let me say 15 min)then your SQL Server
may be experiencing an I/O bottleneck.
"Brian Moran" <brian@solidqualitylearning.com> wrote in message
news:%23r7TWIieEHA.2848@TK2MSFTNGP10.phx.gbl...
> I don't tend to agree with that advice.
>
> On it's own
> <<
> '%Disk Time
> >>
>
> Is not a very reliable indicator of an IO bottleneck. You could easily
have
> a bottleneck if this counter is much lower than 55%. You might NOT have a
> bottleneck if this counter is 55% or higher.
>
> There are many, many more counters which you should take a look. You need
to
> take a look at queue lenght, wait times for disk transfers, time it takes
> per read and write. In addition, there are a host of other counters
> specific to your SAN that you should take a look at.
>
>
> Unfortunately, I'm running a bit late right now and I don't have time to
> write a long message. Tom Davidson from MS has a nice article in SQL
Server
> Magazine that dicusses some of these counters. I believe it might also be
on
> MSDN. It shouldn't be too hard to track down if you search by his name on
> each site.
> --
>
> Brian Moran
>
> "Uri Dimant" <urid@iscar.co.il> wrote in message
> news:u1rJ0yheEHA.3520@TK2MSFTNGP10.phx.gbl...
> > Mike
> > This counter measured how busy a physical array is. In general it should
> be
> > less 55% otherwise you probably jave IO bottleneck.
> >
> >
> >
> >
> >
> > "Mike" <anonymous@discussions.microsoft.com> wrote in message
> > news:c13201c47a1b$4db045c0$a401280a@phx.gbl...
> > >
> > > I have a Windows 2000 Advanced Server with SQL Server 2000
> > > Enterprise Edition on a SAN. What units are the %Disk
> > > Time measured in from Perfmon?
> > >
> > > Is the (% Disk Time E) = (Disk Time E) / (Total % Disk
> > > Time) ?
> > >
> > > Please help me with these questions.
> > >
> > > Thanks,
> > >
> > > Mike
> >
> >
>
>
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