THE SQL Server Blog Spot on the Web

Welcome to SQLblog.com - The SQL Server blog spot on the web Sign in | |
in Search

Browse by Tags

All Tags » Storage » SAN » Performance   (RSS)
  • Performance impact: file fragmentation and SAN – Part V

    SQL Server workloads   So far, the discussions in all the previous posts (1, 2, 3, and 4) on the performance impact of file fragmentation on a drive presented from a high-end enterprise-class disk array are related to disk I/O workloads. Ultimately, you want to know how file fragmentation may impact your SQL Server workloads.   In ...
    Posted to Linchi Shea (Weblog) by Linchi Shea on December 29, 2008
  • Performance impact: file fragmentation and SAN – Part IV

    Lies, damned lies, and statistics!   If you have read my three previous posts (1, 2, 3), you may walk away with an impression that on a drive presented from a high-end enterprise class disk array, Windows file fragmentation does not have a significant performance impact. And I’ve given you empirical data—oh yeah, statistics—to support that ...
    Posted to Linchi Shea (Weblog) by Linchi Shea on December 22, 2008
  • Performance Impact: file fragmentation and SAN – Part III

    256KB Sequential Reads   In my two previous posts (1, 2), I highlighted the fact that while file fragmentation had a huge adverse performance impact on directly attached storage (DAS), it did not have much, if any, impact on the drive presented from a high end enterprise class disk array. That observation was derived from running disk I/O ...
    Posted to Linchi Shea (Weblog) by Linchi Shea on December 10, 2008
  • Performance impact: file fragmentation and SAN – Part II

    1KB Sequential Writes on DAS   There were some questions about the use 1KB sequential writes in my previous post to test the performance impact of file fragmentation on a drive presented from a high end enterprise class disk array.   There were two reasons for testing 1KB sequential writes: ·      SQL ...
    Posted to Linchi Shea (Weblog) by Linchi Shea on December 8, 2008
  • Performance Impact: file fragmentation and SAN -- Part I

    1KB Sequential Writes   It’s well known that disk I/O performance can be severely impacted by fragmentation at the file system level. In other words, when a file is allocated space from many small fragments, its performance can be much worse than when its space is allocated from a single contiguous chunk. The impact is most pronounced with ...
    Posted to Linchi Shea (Weblog) by Linchi Shea on December 7, 2008
  • How did Random I/Os Outperform Sequential I/Os?

    Recently, when I was doing some I/O performance tests on an I/O path, I found that 8K random reads (and writes) significantly and consistently outperformed 8K sequential reads (and writes) in terms of I/O throughput (megabytes per second). I was puzzled. With a traditional hard disk that is made up of a stack of magnetic platters held by a ...
    Posted to Linchi Shea (Weblog) by Linchi Shea on April 4, 2007
  • Should I Use a Windows Striped Volume?

    In Windows Server 2003, you can use the Disk Management console to create a striped volume over multiple dynamic disks (well, you can also create a mirrored, a RAID-5 volume, etc). If these disks (or LUNs) are presented from a SAN, most likely you can stripe across the same storage devices--making up these LUNs--inside the SAN to present ...
    Posted to Linchi Shea (Weblog) by Linchi Shea on March 12, 2007
  • Beware of Shifting SAN

    Let’s say you are trying to determine the performance impact of a neat database design change you have just devised on an application. So you run some tests with the existing design and the tests run for several hours. Coming back the next day, you make the change and re-run the same tests. The test results look fantastic. Now, before you ...
    Posted to Linchi Shea (Weblog) by Linchi Shea on January 3, 2007
Powered by Community Server (Commercial Edition), by Telligent Systems
  Privacy Statement