Click here to monitor SSC
SQLServerCentral is supported by Red Gate Software Ltd.
 
Log in  ::  Register  ::  Not logged in
 
 
 
        
Home       Members    Calendar    Who's On


Add to briefcase

Physical Disk Performance Measurement Expand / Collapse
Author
Message
Posted Wednesday, December 29, 2010 6:02 AM
Forum Newbie

Forum NewbieForum NewbieForum NewbieForum NewbieForum NewbieForum NewbieForum NewbieForum Newbie

Group: General Forum Members
Last Login: Monday, April 1, 2013 6:25 AM
Points: 2, Visits: 192
Hello,

We have a typical RAID 10 (2+2) configuration with 4 HDD on one of our production database server where I observed in perfmon for the drive which is configured with RAID 10 configuration.

Avg. Disk Read Queue Length - 12.51
Avg. Disk Write Queue Length - 0.06

Somewhere I read , I should divide these figures with the no of spindles. Now the question is , should I divide these values by 4 or 2 and what should I interprete from these values ?

Thanks,
Hemant
Post #1040220
Posted Wednesday, December 29, 2010 7:36 PM
SSC-Addicted

SSC-AddictedSSC-AddictedSSC-AddictedSSC-AddictedSSC-AddictedSSC-AddictedSSC-AddictedSSC-Addicted

Group: General Forum Members
Last Login: Tuesday, July 15, 2014 1:10 AM
Points: 401, Visits: 546
I would suggest the answer is two..

Either you have mirrored two spindles two times and then striped the resulting array (RAID 1+0) is which case everything that happens to one spindle MUST happen to the other synchronously or you have striped two spindles two times and then mirrored the results (RAID 0+1), in which case a single write will also have to be written to two physical spindles.

BTW - doing the mirror 1st and then the stripe actually increases your reliability once you get to 6 spindles.
Post #1040681
« Prev Topic | Next Topic »

Add to briefcase

Permissions Expand / Collapse