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• Using SQLIOSim to Diagnose SQL Server Reported Checksum (Error 824/823) Failures

  This is an extension to by previous post about SQLIOSim data integrity testing. http://blogs.msdn.com/psssql/archive/2008/03/05/how-it-works-sqliosim-checksums.aspx SQLIOSim (.exe/.com) is the predecessor to SQLIOStress.   SQLIOSim is SQL Server Read More... Posted Friday, December 19, 2008 7:45 PM by psssql | 1 Comments Filed under: Engine, Tools, SQL Server 2008

• How It Works: SQLIOSim [Audit Users] and .INI Control File Sections with User Count Options

  The Page Audit User is one of the main execution paths for data integrity checking.   SQLIOSim runs test cycles and during each test cycle the [Audit User] section of the .INI configuration file is used.  These workers perform various page Read More... Posted Tuesday, August 19, 2008 9:18 PM by psssql | 2 Comments Filed under: Engine, Tools, How It Works

• How It Works: SQL Server 2005 - Possible data recovery when checksum failure reported

  I and Microsoft will always opt for restore of a backup when corruption of the database is encountered.   This is the only way to safely restore the database to a known state.   All other actions, such as dbcc repair, can remove data Read More... Posted Thursday, May 22, 2008 3:42 PM by psssql | 0 Comments Filed under: Engine, Troubleshooting: The DB Engine, Tools, How It Works

• Microsoft to Increase Use of SQL Server 2005 Best Practices Analyzer (SQLPBA) - So Should You

  I don't want you to be surprised when you see more use of SQLBPA.   It was 18 months ago when the development team approached the support team asking us to help identify issues for SQLBPA.   Several of us, including myself helped identify Read More... Posted Saturday, April 05, 2008 6:21 PM by psssql | 1 Comments Filed under: Engine, Tools

• SQLIOSim is "NOT" an I/O Performance Tuning Tool

  This blog post is to again inform you "NOT" to consider SQLIOSim as an I/O performance evaluation tool!   Every other month or so I get a rash of questions about using SQLIOSim to validate I/O performance and I have to repeat the same Read More... Posted Saturday, April 05, 2008 3:24 AM by psssql | 3 Comments Filed under: Engine, Tools

• How It Works: SQLIOSim - Checksums

  SQLIOSim, like its predecessor SQLIOStress, is designed to read pages it has written and validate the data.   SQLIOSim does this using a checksum algorithm. When SQLIOSim starts up it creates a set of buffers and used the Cryto APIs to generate Read More... Posted Wednesday, March 05, 2008 4:51 PM by psssql | 2 Comments Filed under: SQLOS, Engine, Tools, How It Works

• How It Works: Conversion of a Varchar, RPC Parameter to Text from a Trace (.TRC) Capture

  The Senior Escalation Engineers do various training and mentoring activities. As I do this I thought I would try to propagate some of this information on the blog. This was an interesting issue I ran into this week. The reported problem was that the data Read More... Posted Thursday, January 24, 2008 3:30 PM by psssql | 1 Comments Filed under: Trace, Engine, Tracing, OSTRESS, READTRACE, Tools, RML Utilities, How It Works

• SQLIOSim - Error Request Could Not Be Performed - Unable to get disk cache info

  Both SQLIOSim and SQLIOStress use DeviceIOControl to determine information about the target.   On disk caches are typically not battery backed and when enabled can lead to data loss during a power outage. The utilities attempt to warn the user Read More... Posted Monday, January 14, 2008 7:19 PM by psssql | 1 Comments Filed under: SQLOS, Engine, Tools

• SQLIOSim - Outstanding I/O Warnings

  I have encountered some questions pertaining to the SQLIOSim outstanding IO warnings and I am posting some details.   The Display monitor thread is responsible for updating the display (progress outputs) and checking for long IOs   (CheckForLongIO/ReportLongIo). Read More... Posted Tuesday, April 10, 2007 4:04 PM by psssql | 3 Comments Filed under: Engine, Tools