In the Exchange Server, you may need to send or receive emails, make changes to the mailbox items, or migrate mailboxes across databases or to Exchange Online. You may also need to perform folder or database-level operations. But, do you know that the transaction logs record every such small to major activity? Yes, it performs this task to maintain data integrity and recover data in the event of database corruption.
All the transaction logs, whether committed or non-committed, remain in the Exchange Server unless deleted. Before deleting these logs, admins create a VSS backup through Windows Backup Server (WSB), or any other Exchange-aware backup utility. After the successful VSS backup, the Exchange deletes committed log files automatically to free space for new logs.
However, unintentional deletion of EDB log files can cause issues, necessitating their quick recovery. Let’s discuss this issue in detail and try to find out the possible manual resolution and the automated method using an Exchange recovery tool.
What is the root cause behind the issue?
At times, while eliminating committed logs, you may accidentally delete several uncommitted transaction log files as well. Here, the term uncommitted refers to the files that remained unwritten to the Exchange database. This will lead to database inconsistency, integrity issues, Dirty shutdown errors, and database corruption.
If you want the deleted log file, you will have to recover it before your database starts facing grave issues. This is possible by retrieving the file from the most recent database backup to restore the database to a consistent state. In case of no Exchange Server database backup, the Eseutil utility can help to repair and remount the database.
As you may expect, this manual method can be slow, unproductive, and can cause loss of data. As a suitable alternative, you can use a third-party Exchange recovery tool, such as Stellar Repair for Exchange.
What can be the impact of missing exchange log files?
The Exchange database depends largely on the transaction logs to ensure data integrity and facilitate timely database recovery. Any incident of accidental or deliberate deletion of these files can have an adverse effect on the database tasks and restore operations.
- Database mounting error: Database becomes inconsistent and fails to mount in the absence of log files.
- Data loss risk: Uncommitted transactions stored in the missing transaction log files will vanish permanently.
- Failed database backup: The tasks of database backup and restoration will fail without the log files, especially if there is no recent backup.
- Face the Hard Recovery risks: If no backup exists, admins will have to proceed with Eseutil, a hard recovery method to mount the database. This method discards uncommitted transactions, hence causing further loss of data.
- More downtime: Recovering missing log files can cause more interruptions and hamper productivity
How to recover EDB without log files by using the Eseutil command?
This method can help to recover the Exchange database file, but before proceeding with it, you should be aware that it is not a foolproof method. Moreover, you must back up the current database to deal with any adverse situation arising during the recovery process. Here is the process:
1. Find the existing state of the database
As the starting step, use the Eseutil utility to check the current database state. Run the following command in the Exchange Management Shell Command Prompt:
Eseutil /MH databasename
In the information listed, search for details related to Logs Required and State. If the state shows clean, you can carry out your usual tasks, but if it shows Dirty Shutdown, proceed with the next step.
2. Perform a hard recovery of the Exchange database
In the case of missing log files, the Eseutil soft recovery option using the Eseutil/r parameter will not work. Therefore, you only have the option to perform hard recovery through the Eseutil /p parameter. Before using this method, you should know that
- It does not guarantee a complete Exchange database recovery
- It entails a high risk of data loss, as the process purges the uncommitted and irrecoverable mailboxes
- Failure of this method will revoke the support from Microsoft due to the hardcoding and marking of the database
Steps for hard recovery
To perform a hard recovery, use the command below:
Eseutil/p ‘Exchange database location’
- Check the database state again.
- If it comes out clean, run the Eseutil/d parameter to defragment the database and perform an integrity check.
- In case of no error, run the Mount-Database -Identity name.edb cmdlet. This will mount the recovered Exchange database to the server.
What if hard recovery fails?
In the event of a failed recovery process using Eseutil/p parameter, you will get several error messages, as shown here:
Error -501 (JET_errLogFileCorrupt) – “Log File is Corrupt”
Error -514 (JET_errBadLogVersion) – “Log file generated with different Exchange Server or edition”
Error -515 (JET_errInvalidLogSequence) – “Any log file from the sequence is missing”
Error -533 (JET_errCheckpointCorrupt) – “Checkpoint file is deleted or corrupt”
Considering the vulnerabilities in this method, using automated software will be a comparably much better option.
How to recover EDB without log files by using Stellar Repair for Exchange?
As the Eseutil command has several demerits, this Exchange recovery tool provides a highly convenient and safer recovery method. Stellar Repair for Exchange eliminates the drawbacks and risks associated with the manual methods.
It recovers damaged, corrupt, or deleted files from the Exchange database. In fact, it is ideal to resolve Jet Exchange Error, ‘Dirty Shutdown Error and similar issues that are hard to resolve manually because of the complexities of inbuilt utilities, like EAC, PowerShell, and Eseutil commands. Here are some more of its key features:
- Repairs EDB files and restores mailboxes
- Supports quick mailbox recovery through a parallel processing technique
- Supports Exchange Server 2019, 2016, 2013, and previous versions
- Exports the recovered mailboxes to PST, PDF, EML, HTML, RTF, EML, & HTML
Steps to recover EDB files using Stellar Repair for Exchange
Once you download and install the Exchange recovery tools, the recovery steps are quick and easy.
- Launch the software
- Select the EDB file
- Choose the Scan mode from Quick or Extensive
- Browse the database to view the mailboxes, journals, contacts, calendar entries, and tasks.
- Click the Save button, choose Save as PST, and then select the destination.
- This will start the recovery process
Conclusion
The Exchange database ensures data integrity and data recovery with the help of transaction log files. These files record all types of transactions related to sending or receiving emails, changes in the mailbox items, mailbox migration, etc. Once the activity completes, the admin deletes log files to make way for new log files.
Often, alongside the committed files, the user may delete uncommitted files as well. This can cause big chaos, as the database can become inconsistent and corrupt, leading to loss of productivity and reputation. To recover these accidentally or intentionally deleted log files for a crucial task ahead, you should have a recent, healthy backup of the database for quick restoration of the log file.
If there is no backup file, the only manual resolution is to perform hard recovery through the Eseutil/p parameter. This step results in a significant loss of data as it eliminates uncommitted transactions. To remedy the situation, organizations prefer using a third-party Exchange recovery tool such as Stellar Repair for Exchange.
The tool works proactively in recovering the deleted or damaged database files. It is highly effective in dealing with ‘Dirty Shutdown’ or ‘Jet Exchange’ errors that are difficult to resolve manually, mainly because of the intricacies of built-in Eseutil, PowerShell, or Eseutil commands.