January 22, 2008 at 7:43 am
I have a question regarding the Disk counters in performance monitor.
I am monitoring a server that has 5 logical disks, each logical disk has between 2 and - 8 physical disks. I am a little confused about what perfomance monitor is really showing.
I have the following two counters:
1. object: Physical Disk
counter: avg disk sec/write
instance: _Total
2. object: Logical Disk
counter: avg disk sec/write
instance: D:
In case No. 1, is it showing the average disc sec/write off all physical disks in the server ?
In case No 2 is it showing the average of each physical disk in volume D:?
Thank you in advance to help me clarify what it really means!
January 22, 2008 at 7:58 am
Next time, you may want to look at a Windows site for this type of information, as this is a SQL Server site.
Here's a brief overview to your question:
The Physical Disk counter is showing Avg. Disk sec/write for all physical disks on your system
The Logical Disk counter is showing Avg. Disk sec/write for logical disk on your system, which with be either other partitions or Raid disk (e..g Raid1, Raid5 or Raid10). When monitoring logical disk, you will need to consider # of disks supporting the logical volume in your results.
Here's a good reference point:
Cheers,
Phillip Cox
January 24, 2008 at 12:53 pm
sorry but i disagree about the post, storage and server o/s tuning are all part of the DBA skill set and this is a valid question on a SQL site.
just to clarify - physical refers to the actual array or physical disk
logical is the partitions defined upon your physical disks.
e.g. if your home pc has one hard disk and you set a C: and D: partition then the logical disks are C: and D: but you only have one physical disk. generally on servers you'll have hardware arrays so if each array has only one partition physcial and logical disks will be the same.
[font="Comic Sans MS"]The GrumpyOldDBA[/font]
www.grumpyolddba.co.uk
http://sqlblogcasts.com/blogs/grumpyolddba/
January 25, 2008 at 2:16 am
Yep...got to agree with colin here...
January 30, 2008 at 7:57 am
My thoughts exactly Colin.:)
January 30, 2008 at 8:09 am
Hey,
My mistake, as this is something I do on a regular basis.
I was over generalizing and thank everyone for giving me a tilt!
Thanks,
Phillip Cox
March 26, 2010 at 12:45 am
Are you a professionnal ?
You never should be partitionning a disk ! Never ! Thid was not made by microsoft for this use. This was made to bypass the logical format from a larger hard drive, for not to loosing any storage capacity. It has never been made for your convenience. When you sector a wheel in 3 equal parts, don't be surprised if any sector have 33% of performances at the end. Also, using partitionning would create multiple instances of undesired extented partition tables. And we all know (The real professionnals) that this can be a real danger with mixed partitionned disks as logical, primary and extented partitions would mix in an undisired way, causing MFT to mix down with disk signing...
So, you should never consider a partiotionning in all your life untill you can't do it because of File system limitations. And you must understand then that there are multiple risks to do it as this is a patch, not a rule !!!
March 26, 2010 at 4:09 am
famille.espie (3/26/2010)
Are you a professionnal ?You never should be partitionning a disk ! Never ! Thid was not made by microsoft for this use. This was made to bypass the logical format from a larger hard drive, for not to loosing any storage capacity. It has never been made for your convenience. When you sector a wheel in 3 equal parts, don't be surprised if any sector have 33% of performances at the end. Also, using partitionning would create multiple instances of undesired extented partition tables. And we all know (The real professionnals) that this can be a real danger with mixed partitionned disks as logical, primary and extented partitions would mix in an undisired way, causing MFT to mix down with disk signing...
So, you should never consider a partiotionning in all your life untill you can't do it because of File system limitations. And you must understand then that there are multiple risks to do it as this is a patch, not a rule !!!
:blink: So, you thought it worth resurrecting a year-old thread to post that as your first-ever contribution to this site? :blink:
Poor effort.
Paul White
SQLPerformance.com
SQLkiwi blog
@SQL_Kiwi
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