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Apr 17 2008   5:07PM GMT

DATABASE CORRUPTION IN EXCHANGE…PRT3

B00M3R John Bostock Profile: B00M3R

 In this section we will look at exporting the damaged page file to a text file. Name the txt file in relation to the page file itself so as below this relates to page 3106. Therefore, you could use the following command to create a file called 3106.TXT.

This must be run from the \Program Files\EXCHSRVR\BIN directory

eseutil /m “d:\program files\exchsrvr\mdbdata\pri

1.edb” /p3106 >3106.txt

After running the command you will see the text file created.
Microsoft(R) Exchange Server(TM) Database Utilities
Version 6.0
Copyright (C) Microsoft Corporation 1991-2000.  All Rights Reserved.
Initiating FILE DUMP mode…     
Database: d:\program files\exchsrvr\mdbdata\priv1.edb
Page: 3106
pgnoThis <0x02360004,  4>:  3106 (0x00000064)
objidFDP <0x02360018,  4>:  11 (0x0000000b)
ulChecksumParity <0x02360000,  4>:  466674925 (0x1bd0e4ed)
dbtimeDirtied <0x02360008,  8>:  216893 (0x0000000000034f3d)
cbFree <0x0236001c,  2>:  4026 (0x0fba)
ibMicFree <0x02360020,  2>:  3265 (0x0cc1)
itagMicFree <0x02360022,  2>:  2 (0x0002)
cbUncommittedFree <0x0236001e,  2>:  0 (0x0000)
pgnoNext <0x02360014,  4>:  0 (0x00000000)
pgnoPrev <0x02360010,  4>:  0 (0x00000000)
fFlags <0x02360024,  4>:  3141 (0x00000c45)
Parent of leaf
Internal page
Root page
FDP page
Multiple Extent Space (ParentFDP: 97, pgnoOE: 340)
Index page (non-unique keys)
TAG   0    cb:   16    ib:    0    offset:  28 -  37    flags: 0x0000
TAG   1    cb:    6    ib: 3259    offset: ce3 – ce8    flags: 0x0000
Operation completed successfully in 1.91 seconds.

Things to Note:
When I generated my report, I picked page number 3106 at random. As you can see at the bottom of the text file, page 3106 is an index page. If you ever have to repair a 1018 error, you’ll usually lose all of the data on the page that you encountered the error on. Of course, that’s assuming that the error occurred on a leaf page. An index page links too many other pages. Therefore, if the page that I selected had actually been damaged, I might have lost the index page and all related leaf pages. This could possibly lead to a complete breakdown of the entire database. Fortunately, Exchange is really good about rebuilding structural components, such as index pages.

When you browse the file you can see the page number and previous page number and the next database pages. Also you should pick out the checksum parity bit number and you can use all this info when attempting to repair the database.

You also need to realize that you can get false 1018 errors. Now and then a faulty disk cache or a faulty hard drive will cause data to be read from a location other than the correct location specified by Exchange. When this happens the database is initially corrupt and you have a serious problem on your hands because the disks actions will soon cause the database to become totally corrupt.

At this stage you probably really need to understand about repairing a corrupt database which Ill talk about more in another post. For now understand how to read the txt file which will help you resolve and repair.

 

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