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SQL Server Disk Performance

3 posts in Windows NT Last posting was on 1997-11-03 22:16:32.0Z
Alan Reid Posted on 1997-10-10 08:20:12.0Z
From: "Alan Reid" <alan.reid@baesema.co.uk>
Subject: SQL Server Disk Performance
Message-ID: <01bcd55e$351e6dc0$c901a8c0@nmi-spare-04>
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Date: Fri, 10 Oct 1997 04:20:12 -0400
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Article PK: 1081561

I am running SQL Server on Windows NT 4, but am unable to use asynchronous
disk I/O, as SQL Server always says it is disabled at the o/s level.

This results in disk i/o which is significantly slower than that achievable
on the same system outside of SQL Server.

How can I enable asynchronous i/o?

Thanks
Alan Reid


Philip Stafford-Jones Posted on 1997-11-03 22:16:32.0Z
Message-ID: <345E4D40.7A80@sybase.com>
Date: Tue, 04 Nov 1997 09:16:32 +1100
From: Philip Stafford-Jones <psj@sybase.com>
Reply-To: psj@sybase.com
Organization: Sybase, pse server europe
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CC: alan.reid@baesema.co.uk
Subject: Re: SQL Server Disk Performance
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Alan Reid wrote:
>
> I am running SQL Server on Windows NT 4, but am unable to use asynchronous
> disk I/O, as SQL Server always says it is disabled at the o/s level.
>
> This results in disk i/o which is significantly slower than that achievable
> on the same system outside of SQL Server.
>
> How can I enable asynchronous i/o?
>
> Thanks
> Alan Reid

If you are using either SQL Server 10 or 11 it always uses
asynchronous I/O independant of what is set through sp_configure
or what is erroneously reported in the errorlog.

I have confirmed this in the SQL server code, this message
is written to the errorlog even when asynch i/o is enabled
(which it *always* is).

So please rest assurred that Sybase SQL Server 10 and 11 do
use asynchrous i/o.

If you are unhappy about the error message please raise
a calltrack with Sybase Tech Support, who can enter a request
for a bugfix for this anoying error message.

I hoep this clarifies the situation,
Phil Stafford-Jones
Senior Product Specialist Engineer.


Francois Clement Posted on 1997-10-28 17:19:14.0Z
Message-ID: <34561E92.9B5@castsoftware.com>
Date: Tue, 28 Oct 1997 18:19:14 +0100
From: francois clement <f.clement@castsoftware.com>
Reply-To: f.clement@castsoftware.com
Organization: Cast SA
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Subject: Re: SQL Server Disk Performance
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Alan Reid wrote:
>
> I am running SQL Server on Windows NT 4, but am unable to use
> asynchronous disk I/O, as SQL Server always says it is disabled at the o/s level.

What is the sql server version ?
What kind of devices do you use (raw device or OS file) ?
What are the messages in the errolog during the SQL Server startup
regarding the devices ?