[database data recovery] data recovery case of insufficient disk space of SQL Server database

Database data recovery environment ：

A brand of server stores 2 Group raid, A group of raid1（2 Block hard disk ）, A group of raid5（5 Block hard disk ）;
There are SqlServer database .

Database failure ：

Deposit SqlServer The partition of the database is insufficient due to the increase of the amount of data , The administrator generated a in another partition .ndf File and point the database path to this partition to continue using , After a period of time, the database fails and reports an error , Prompt connection failure ,SqlServer The database cannot attach queries . The administrator then tried to recover the data, but failed to recover the data , So contact our data recovery center for data recovery .

Database data recovery process ：

1、 The backup data . The server data recovery engineer will mirror and back up all disks stored in the failed server .

2、 Database failure analysis . because SqlServer The disk partition where the database file is located is insufficient , The database doesn't work , There is a logic error . Analysis storage RAID1 and RAID5 Structure , According to the obtained raid The information is virtual reorganized RAID1 and RAID5 And check the data . Because after the database failure , The administrator has tried to restore the data of the database in the original environment many times , The original database file has been changed 、 Cover , Disk space has been repeatedly erased and written , Therefore, it is impossible to repair the database file after the administrator has tried to restore it many times . Fortunately, the administrator failed in the database , A database file was backed up before attempting recovery .

3、 Database repair . Try attaching the previously backed up database file to the database , Result attachment failed , The error message is as follows ： 

 

The error indicates that the primary database file does not match the secondary database file , Database data recovery engineer view .ndf The bottom of the file , Find out .ndf There's almost no data in the file . Try to cancel .mdf Document and .ndf The relationship between files , Only .mdf There are still error prompts when attaching files ： 

 

Error prompt log file （.ldf） And database files （.mdf） Mismatch . So the database data recovery engineer tries to attach the database without database , Attach success . But the database system table was found to be corrupt , Not working properly .

 

The database data recovery engineer tries to repair the system table of the database , But the system table is seriously damaged and cannot be repaired . 

Parsing database records in database files , The North Asia data recovery engineer prepares corresponding programs to extract the database records in the database files , Analyze the database backup to obtain the table structure in the database , Reconstruct the table structure and import the extracted database records into the new table .

data validation ：

The administrator verifies the extracted database records , Confirm that all data is completely recovered . By the way, just to remind you , In the process of using the database , Reasonably allocate the disk space where the database file is located , Clean up the garbage data in time , Ensure the normal operation of the database 、 Safe operation .