How to Repair LDF File with Corrupt SQL Server Database Logs?
Learning how to repair LDF file can be tricky for SQL users. Nowadays, we are getting a lot of user queries regarding SQL LDF recovery task. Therefore, we are going to learn how to repair SQL Server database with a corrupt log file safely. Along with the solutions, critical causes of corruption in the LDF file and related errors are also mentioned below.
SQL LDF or Log Data File is the file format in which SQL Server stores the transaction log entries. For every transaction in SQL Server like CREATE, INSERT, DELETE, etc a user performs, the system makes a log. This log holds information like transaction type, user ID who executed that transaction, time stamp, etc. This is helpful in Rollback commands, evidence in court, & other scenarios.
To find out the detailed solution for fixing all the damaged in the Log file of the SQL Server, users must understand the causes of the damage. Moreover, understanding the related errors can be really helpful at the same time to rebuild transaction log in SQL Server DB.
Corruption Causes in SQL Server Log File (LDF)
Users need to learn how to repair LDF file in SQL just because of the damage in the LDF file. Therefore, it is of utmost significance for users to find out the corruption reasons for the same. Here we have mentioned the top causes of why log file corrupts.
- Hardware Component Failures: Hardware component issues are the major causes of log file corruption. Not just log but it can cause any file to corrupt. Bad sectors in storage drives are the most common in these scenarios.
- Sudden System Crashes: Unwanted system crash is also a significant reason. Abrupt shutdowns or power outages stop the ongoing SQL transaction in between which results in corrupt data including the log files.
- Cyber Attacks on SQL Server: Different types of SQL Injection attacks, malware, ransomware, etc threats are the causes where the file gets corrupted on purpose by non-ethical elements. Thus, users must maintain database integrity.
- SQL Server Version Bugs: We often recommend users update their SQL Server or patch the SQL Server. This can eliminate SQL bugs that can cause severe level corruption in the log files forcing users to restore LDF file SQL server.
- Storage Media Issues: Physical damage to the storage media at the place of the log file can cause damage. Over time, this damage can be reflected by the log files in the form of corruption.
- Disk Space Issues: Insufficient space in the drive where the LDF files are accommodated is another issue that users need to work on. They must have adequate space to store the files.
- Missing Indexes: Missing indexes and corrupted logs are somehow interrelated to each other. Corrupted log files can result in missing indexes & vice versa. Therefore, users must audit SQL server regularly.
- Operating System Errors: File system errors or driver issues originating from the operating system often cause a threat to log file integrity & eventually result in LDF corruption.
SQL LDF Recovery Importance for Related Errors
Due to the above-mentioned corruption causes, users need to learn how to repair SQL Server database with a corrupt log file safely. However, it is equally significant for users to find out the errors they can get because of such corruption issues of LDF files.
Some of these common errors are:
#1 File Activation Failure Error
This file activation failure error occurs when the LDF file location has issues due to the above reasons. The error message looks like this.
File activation failure. The physical file name ‘C:\Program Files\Microsoft SQL Server\MSSQL13.MSSQLSERVER\MSSQL\DATA\XXX.ldf’ may be incorrect. Diagnose and correct additional errors, and retry the operation.
This error is mostly because of the log file & backup file. This is related to the operating system errors that cause troubles in the usual SQL system.
Operating system error 23 (failed to retrieve text for this error. Reason: 15105) on file “C:\Program Files\Microsoft SQL Server\MSSQL10_50.MYSERVER\MSSQL\DATA\MY_DATABASE.ldf” during CheckLogBlockReadComplete
#3 Failed to Attach Log File Error
When users have some issues in the log file or the primary file, they might face issues in connecting to the database.
Could not open new database ‘Your_DatabaseName’. CREATE Database is aborted
Now let’s move towards the solution to get an in-depth understanding of the entire operation.
How to Repair SQL Server Database with A Corrupt Log File?
We have three solutions to get the desired results. However, it is quite evident that not all of them are ideal for every user. We are mentioning all the solutions below including automated & manual ones to let users get the best results. Here, we are going to include the SSMS method, T-SQL Method, & automated tool to execute the SQL LDF recovery task.
#1 SSMS Method to Restore LDF File SQL Server
Prerequisites
- This SSMS method is only for the users having a backup file of the database. If users are missing the BAK file, they can move directly toward the other methods.
- Make sure users have an active SQL Server with SSMS(SQL Server Management Studio) to restore LDF file SQL server database.
Step 1. Launch SQL Server Management Studio & Connect to Database
Step 2. Go to Object Explorer >> Right Click Database >> Click Restore Database
Step 3. In the “Source for Restore Section”, Simply Select the From Device Option
Step 4. Select Backup Media & then Hit the Add Button in Specify Backup Window
Step 5. Choose the Backup File & Click the OK Button to Proceed
Step 6. Now, Users Will See the Backup Files on Database Restore Window
Step 7. Configure Settings Option Under Select a Page Section to Complete
Step 8. In the Restore Options section, Select Desired Checkbox & Click OK.
#2 How to Repair LDF File Using T-SQL Commands
In case, users are technically proficient, then only they should rely on the command line method. Here, a few SQL commands are required to execute in order to witness the desired results.
1. Set the Database into Emergency mode using the below command:
ALTER DATABASE SET EMERGENCY, SINGLE_USER GO
Users can bring the database online using the above command without the need of a log file.
2. Run DBCC CHECK command with Repair_Allow_Data_Loss option as shown below:
DBCC CHECKDB ('TestTRNLogCorrupt', REPAIR_ALLOW_DATA_LOSS)
Keep in mind that this command can result in minor data loss where the data is highly corrupted.
3. Finally, if there is still some corruption left, users need to run the below command to finish learning how to repair LDF file with ease.
ALTER DATABASE [name_of_log_file] REBUILD LOG ON (NAME= logicalname, FILENAME='C:\Program Files\Microsoft SQL Server\MSSQLn.MSSQLSERVER\MSSQL\DATA\file_name.ldf')
In case this method fails, or users face difficulties to execute, they can always switch to the most user-friendly yet effective automated solution. Let’s proceed to our final method for more detail.
#3 Best SQL LDF Recovery Solution
To how to repair SQL Server database with a corrupt log file, users need to download the expert-recommended SQL Server Log Analyzer tool. This advanced solution can help users recover as well as repair the corrupted SQL LDF files without any hassles. It allow users to examine the log files easily with multiple filter options. Also, users can tackle the SQL Log file growing rapidly problem with this solution.
Download the tool & then fix the damaged log file using the four simple steps:
Step-1. Launch the Tool & Click on the Open button.
Step-2. Select the Online or Offline mode & Add LDF File.
Step-3. Preview all Log Files after scanning them in detail
Step-4. Click the Export option to restore LDF file SQL server.
The Conclusion
Finally, we all are aware how to repair LDF file in SQL Server database with a corrupt log file. However, not all the solutions mentioned are easy for users. The T-SQL query method is often considered the riskiest way.
Therefore, SQL LDF recovery should only be relied on the automated solution. This is why various IT experts, SQL MVPs, & millions of users trust this utility. In a nutshell, this problem is critical & users must know all the methods. However, selecting the easiest solution is the ideal decision.