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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...
View ArticleHow 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...
View ArticleHow to Corrupt a SQL Server 2005 Database
How can you corrupt an online SQL Server 2005 database? Okay, why would you want to do that? Well, let's say because you want to test out some DBCC commands.If you take a SQL Server 2005 database...
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SQL Server and SANs: The QueueDepth Setting of a Host Bus Adapter (HBA)
Too many DBAs tend to view a drive presented from a Storage Area Network (SAN) as something of a monolithic nature. They look at the drive as if it had some intrinsic performance characteristics. This...
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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...
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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...
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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...
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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,...
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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...
View ArticleSAN vs. Disk Arrays: It goes a long way to be slightly more specific!
In the SQL Server communities, it's common to hear people talking about HP SAN, EMC SAN, 3Par SAN, and so on as if there were such things as HP SAN, EMC SAN, etc. Technically, SAN stands for Storage...
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