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Monday, March 31, 2014

VSS default settings prevent Integrity Check on large databases

Recently we encountered a customer, who got the following error while doing DBCC Checkdb /Integrity check on his large database.

Error: 17053, Severity: 16, State: 1.
"Operating system error 665(The requested operation could not be completed due to a file system limitation) encountered"
OR 
Error: 17053, Severity: 16, State: 1.
"The operating system returned error 665(The requested operation could not be completed due to a file system limitation) to SQL Server during a write at offset 0x00001447cd6000 in file 'X:\SqlDataFiles\LargeDB.ndf:MSSQL_DBCC45'. Additional messages in the SQL Server error log and system event log may provide more detail. This is a severe system-level error condition that threatens database integrity and must be corrected immediately. Complete a full database consistency check (DBCC CHECKDB). This error can be caused by many factors; for more information, see SQL Server Books Online."
The error in the dbcc checkdb is due to a default limitation in VSS, which DBCC is using to complete a full database consistency check in the background.
By default a VSS snapshop may not be larger than 10% of the size of the drive. This can be changed be going to Computer Management -> Disk Management -> Select Properties on all the drives that contains the database -> Select the pane Shadow Copies" -> Select Settings -> Select the redio button "No limit"



This removes the VSS limitation that causes the Error 655 

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