A safe approach to database recovery in case of IAM chain corruption in SQL Server 2008

SQL Server 2008 is the best tool for database developers and administrators as it incorporates some of the major improvements over the earlier versions. It has support for large data sets and the ability to handle multiple users. The new 'Performance Studio' provides you with a collection of tools for easy monitoring and troubleshooting the system. It allows you to build up an efficient policy management system and help database administrators in carrying out various administrative tasks. Regardless of all these benefits, there are various contingencies that lead to corruption in the SQL databases. The potential reasons behind database corruption include virus infection, hardware failures, operating system bugs, etc. As a consequence, all the valuable objects in the SQL database become inaccessible. In order to recover your lost invaluable data, you should perform SQL recovery through proficient third-party software.


IAM chain corruption is a common occurrence on SQL Server 2008. This is usually accompanied by the below given error by DBCC CHECKDB:


"Msg 2576, Level 16, State 1, Line 1 
The Index Allocation Map (IAM) page (0:0) is pointed to by the previous pointer of IAM page (1:153) in object ID 0, index ID -1, partition ID 0, alloc unit ID 72057594042384384 (type Unknown), but it was not detected in the scan."


The system table 'sysallocunits' usually has a reference to the first IAM page, the root page, and the first page. The above error says that metadata does not include a reference to the first IAM page in the IAM chain (page 1:153). This indicates corruption in the 'sysallocunits' system table.


If you try to use the 'repair_fast' and 'repair_rebuild' options in this case, you may get no significant results. In order to resolve the issue, you may try the following series of steps:

•     Start a transaction
•     Write the rowcounts for all system objects and tables in your database.
•     Now use CHECKDB for repairing the database.
•     Make sure that the problem is resolved and the error is not seen again
•     Rerun DBCC CHECKDB to verify the database.
•     Examine the rowcounts once again.
•     Commit the transaction

The 'repair_allow_data_loss' should be the minimum repair level for this case. If the problem persists, you may try professional SQL 2008 database recovery software. These third-party tools extensively scan SQL databases to recover damaged or inaccessible objects, including tables, views, indexes, constraints, triggers, etc. Moreover, they are compatible with Windows 7, Server 2008, Vista, Server 2003 and XP.

Read More

Use Advanced SQL Recovery Tool to Repair MDF Files

If you are regularly using Microsoft SQL 2008, then you might have faced several situations wherein you are unable to mount a SQL Server database. Such cases are sometimes cause very serious problem such as database corruption or complete inaccessibility of the SQL database thereby making your database very insecure. These corruption scenarios can arise due to various reasons such as automatic system shutdown when the database is running, power failure, virus infections, hardware issues, human errors etc. In such cases, you should find the cause of database corruption and try to repair SQL. If you are unable to repair SQL(.MDF) file, then you should use an advanced MDF file repair software to perform SQL database recovery.

Consider a Practical scenario wherein you try to open a SQL database while using MS SQL Server 2008. However, database does not open. An error message appear as a result, which is:

"Database '%.*ls' cannot be opened due to inaccessible files or insufficient memory or disk space. See the SQL Server error log for details."

Cause:

The root cause of above error message is that the database could not be mounted because some resources or files are missing.

Resolution:

To resolve above error message, you should repair MDF file. To do this, you need to perform the given below methods:

Check Error log: Firstly, You should check error log to get the details about resources such as disk space, memory, permission failure, etc that may have caused the above problem.

Confirm the location of SQL Database files: You should check the location of MDF or LDF files and verify whether Database Engine account has required credentials to access these SQL Database files.

Restart Database: Finally, you should restart the SQL Server database with the help of ALTER DATABASE query. This query sets the SQL Server database to online.

Above described methods should be able to set the SQL database up. However, if you still are unable to mount the database then you should use a SQL repair tool to repair SQL Server database. Such MDF database repair software are read-only in nature.

Stellar Phoenix SQL Database Recovery software is an SQL database repair tool that repairs MDF file and NDF file alike. Specifically designed for MSSQL Server 2000, 2005, 2008 and 7.0. This MDF file repair tool restores various database objects such as collations, tables, stored procedures, triggers, defaults and many more. In addition, this repair mdf software preserves the relationship among the database tables.

Read More

Binary Tree Corruption cause Data Loss in SQL Server

Microsoft SQL Server database supports binary tree indexes for fast query. The pages of Binary tree index are known as index nodes, the top node of binary tree is known as root node. However, the middle nodes are known as branch nodes and bottom nodes are known as leaf nodes. If table indexes get damaged, SQL Server database shows an error message and you unable to access your SQL database. To resolve such situations, you should use your most latest backup and restore the lost data. Sometimes, backup fails to restore the database and thus, you need to use SQL database recovery software.

You are working on SQL Server database wherein, You might get below error message:

Server: Msg 8936, Level 16, State 1, Line 1
Table error: Object ID O_ID, index ID I_ID. B-tree chain linkage mismatch. P_ID1->next = P_ID2, but P_ID2->Prev = P_ID3.

Root Cause of Problem:

The above error message appears when SQL Server database find a break in logical page chain at any level of Binary tree. It can happen at any level of binary tree including root, middle and leaf nodes.

Resolution:

For solving the above error message, you should follow the given below steps:

Run the hardware diagnostics as above problem could occur due to hardware problems. Fix the hardware problems, if any.
If the problem persists still then restore the corrupted SQL Server database from a latest and clean backup.
In case of unavailability of valid SQL server backup, you could run DBCC CHECKDB command to find the amount of corruption and note the repair clause. Again run DBCC CHECKDB command with suggested repair clause.
If database still unaccessible, you should use an advanced SQL database recovery tool.

These SQL database recovery tools are advanced tools that can effectively repair and restore corrupted SQL databases. Such tools are equipped with rich GUI, to-the-point documentation. You can freely use these software for repairing and restoring corrupted or damaged SQL Server database in any case of SQL database corruption.

The most trusted SQL Database recovery tool by the many database administrator is Stellar Phoenix SQL Recovery tool. It is a complete repair software for damaged or corrupted SQL Server databases. This software supports mdf recovery for SQL Server 2008, 2005 and 2000. It is available with advanced graphical user interface and restores all database objects like tables, triggers, user defined data types, stored procedures, collation views, rules and many more. The software is compatible with Windows Vista, XP, 2003, 2000, NT and 7.0.

Read More

Recover SQL Server Database from Corrupted Table

Sometimes when you want to update or delete SQL server database table and got an error message that shows your SQL server database table has been corrupted. This may happen by the several reasons some of them are improper system shutdown, virus attack, hardware failure, power failure and many more. At this situation you will be unable to access your SQL server database table. For fixing this problem you should use an advanced SQL server recovery software that will repair and restore your damaged SQL server database table.

Consider a practical scenario wherein, you may encounter the given below error messages while your are trying to update, delete or open an SQL server database table:

“Error: 644, Severity: 21, State: 5
Could not find the index entry for RID '1613b1000000100' in index page (1:189), index ID 7, database 'TestDB'..
Error: 8646, Severity: 21, State: 1
The index entry for row ID was not found in index ID 7, of table 2009058193, in database 'test644'.”

Particularly the above error message occur on the non-clustered index of Microsoft SQL server database but sometimes this problem also occurs with the clustered SQL server database database.

Resolution: For restoring corrupt SQL server database table, you have four option which are given below:

Fix Hardware Issue: Check the hardware of the system if you find any faulty hardware then replace it with the new one.
Restore from Backup: Restore it from the latest backup, if backup is clean and updated.
Run DBCC CHECKDB: Run this command to fix the problem.
Re-built Indexes: If possible then rebuilt indexes of table but it is not the better idea.

After performing three above steps and you are still unable to fix the problem then the best idea is to buy an advanced third party SQL recovery software to fix the problem.

Stellar Phoenix SQL Database Recovery is an MDF recovery software that is able to repair MDF as well as NDF files from all instances of corruption. It repairs corrupted MDF, NDF files created in SQL Server 2000, 2005, and 2008. This MDF file repair tool is capable of recovering various database components such as tables, stored procedures, views, collations, queries, triggers, etc. It is compatible with Windows 7, Vista, Server 2003, XP, and 2000.

Read More