today I want to attach a case that I've ever read in my current company, has to do with the importance of the disk block size environments data base.
They are attached and read they recommend. All should take into account the block size for the disks that hold your data files.
Details:
Detailed
description can be found at Autotrac Record Link:
<provide link> NA
Client
complains about performance and transactions are not at the optimal
range according to the client.
The
SQL DBA should check the disk IO based on input from the client as
there could be an issue with the block size previously used to format
the disks prior to MS SQL being installed on the drives.
A
test case scenario with a 900 swipe a second credit card simulator:
The
disk response time in milli seconds was unacceptable (started
increasing past .5\.7 and 1+ when reached an average of 4,000-4,500
transactions per second on 2 drives ). SQL DBA viewed the block
sizes used to format the 2 drives with bad performance and found that
Partition starting offset sizes of 32kb. Although disruptive to make
the change, the data was removed, the drives reformatted with 64kb
blocks and the test case scenario achieved an average of 7,500 \ max
of 13,000 transactions per second while staying under the .5 ms
second disk response time.
Client
complaints regarding SQL performance, transactions not at the optimal
range
Ed,
Why after checking (what typically does the SQL dba check for when
client complains of performance or transactions going to slow?
On
the OS Server, local disks or storage devices(mount points):
To
check for block size used, you go to Start --> run --. and type:
msinfo32 and hit enter. Navigate as seen below and view the
partition starting offset and as viewed below this would be a 32kb
block size. This is normally not optimal for MS SQL Server
performance. This is also the default for Windows Server 2003 systems
when not 64kb specified during disk format. Newer OS's such as
Windows 2008 use a larger block size and partition alignment works
out of the box usually.
This
would be a disruptive change if block size were found at 32 KB. The
SA would need to be contacted, the data would need to be removed
before the change from 32 KB to 64 KB is made and the device would
need to be reformatted and then data loaded back and tested.
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