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It appears that we are having a problem with the disk i/o speed on our Windows 2003 Enterprise Edition server (64-bit). As we were initializing a database that created two 1G tablespaces on 3 different machines, it became obvious that the two smaller machines (each 32-bit Windows 2003 Standard Edition with less RAM) killed the larger machine when creating the files. The larger machine took 10x as long to create the tablespaces than did the other machines.

Now, I am left wondering how that could be. What programs or scripts would you guys recommend for tracking down the I/O problem? I think the issue may be with the controller card (all boxes are hardware RAID 10, but have different controller cards), but I would like to check the actual disk I/O speed as well, so I have some hard numbers to work with.

Any help would be appreciated.

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migrated from stackoverflow.com May 24 '10 at 14:36

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What database is used? And under what conditions is dataset initialized? –  FractalizeR May 24 '10 at 15:05
    
We are using MySQL 5.1.45 64-bit. We were running all MyISAM tables, but just switched the write intensive tables to InnoDB. The Avg. Disk Queue Length is through the roof, but CPU has come down from 99% to 5%! So, it still appears that the disk I/O is our main culprit, but I don't know how to properly ascertain that. I am looking at I/O Reads in Process Explorer and getting 10 million and I/O Writes is 5 million. –  Jonathon May 24 '10 at 15:08

2 Answers 2

up vote 1 down vote accepted

Try benchmarking the 'service-bare' machine with IOZone, this will tell you if you have an IO-subsystem or application-level issue.

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Could this help?

MSDN : Database File Initialization

From the article:

Data and log files are initialized to overwrite any existing data left on the disk from previously deleted files. Data and log files are first initialized by filling the files with zeros when you perform one of the following operations:

  • Create a database.
  • Add files, log or data, to an existing database.
  • Increase the size of an existing file (including autogrow operations).
  • Restore a database or filegroup.

File initialization causes these operations to take longer. However, when data is written to the files for the first time, the operating system does not have to fill the files with zeros.

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