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Corrupting Databases on Purpose Using the OrcaMDF Corruptor | Mark S. Rasmussen

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Corrupting Databases on Purpose Using the OrcaMDF Corruptor | Mark S. Rasmussen Mark S. Rasmussen improve.dk About Me Pages Categories Archive Nov 05 2013 Corrupting Databases on Purpose Using the OrcaMDF Corruptor .NET , SQL Server - Internals , SQL Server - OrcaMDF , SQL Server Comments Sometimes you must first do evil, to do good. Such is the specimen when you want to strop your skills in self-indulgence recovery of SQL Server databases. To requite me increasingly material to test the new RawDatabase functionality, I’ve now widow a Corruptor matriculation to OrcaMDF. Corruptor does increasingly or less what the name says - it corrupts database files on purpose. The self-indulgence itself is quite simple. Corruptor will segregate a number of random pages and simply overwrite the page completely with all zeros. Depending on what pages are hit, this can be quite fatal. I shouldn’t have to say this, but just in case… Please do not use this on anything valuable. It will fatally untruthful your data. Examples There are two overloads for the Corruptor.CorruptFile method, both of them return an IEnumerable of integers - a list of the page IDs that have been overwritten by zeros. The pursuit lawmaking will untruthful 5% of the pages in the AdventureWorks2008R2LT.mdf file, without which it will output each page ID that has been corrupted. You can specify the percentage of pages to untruthful by waffly the second parameter. var corruptedPageIDs = Corruptor.CorruptFile(@"C:\AdventureWorks2008R2LT.mdf", 0.05); Console.WriteLine(string.Join(", ", corruptedPageIDs)); 606, 516, 603, 521, 613, 621, 118, 47, 173, 579, 323, 217, 358, 515, 615, 271, 176, 596, 417, 379, 269, 409, 558, 103, 8, 636, 200, 361, 60, 486, 366, 99, 87 To make the self-indulgence hit plane harder, you can moreover use the second overload of the CorruptFile method, permitting you to specify the word-for-word number of pages to corrupt, within a unrepealable range of page IDs. The pursuit lawmaking will untruthful exactly 10 pages within the first 50 pages (zero-based), thus hitting mostly metadata. var corruptedPageIDs = Corruptor.CorruptFile(@"C:\AdventureWorks2008R2LT.mdf", 10, 0, 49); Console.WriteLine(string.Join(", ", corruptedPageIDs)); 16, 4, 0, 32, 15, 14, 30, 2, 49, 9 In the whilom specimen I was extraordinarily unlucky seeing as page 0 is the file header page, page 2 is the first GAM page, page 9 is the marching page and finally page 16 is the page that contains the typecasting unit metadata. With self-indulgence like this, you can be unrepealable that DBCC CHECKDB will be giving up, leaving you with no other volitional than to restore from a backup. Or… You could try to recover as much data as possible using OrcaMDF RawDatabase, but I’ll get when to that later :) Mark S. Rasmussen I'm the CTO at iPaper where I petting with databases, mold lawmaking and maintain the overall technical & team responsibility. I'm an voracious speaker at user groups & conferences. I love life, motorcycles, photography and all things technical. Say hi on Twitter, write me an email or squint me up on LinkedIn. CATEGORIES .NETAS/Flex/FlashAmazon Web ServicesComputer ScienceConferences and PresentingIISLifeMiscMiscellaneousPerformancePokerSQL ServerSQL Server - CommunitySQL Server - Data TypesSQL Server - InternalsSQL Server - OptimizationSQL Server - OrcaMDFSQL Server - TricksTestingTools of the TradeUmbracoVisual StudioWebWindbgWindows ARCHIVE 201420132012201120102009200820072006 Copyright © 2014 Mark S. Rasmussen