VMFS Recovery

Recovers data from ESX server

Typical Issues with VMFS on ESX/ESXi Servers
and their Solutions



  • Corruption
    • Metadata Corruption: This can occur due to hardware failures, software bugs, or power outages, leading to loss of file system metadata and making data inaccessible.

    • File System Corruption: Improper shutdowns, crashes, or issues during VMFS volume expansion can cause file system corruption.

  • Performance Issues

    • Fragmentation: Over time, files can become fragmented, leading to degraded performance.

    • I/O Contention: High I/O loads from multiple VMs can cause performance bottlenecks.

  • Capacity and Space Management

    • Overprovisioning: Thin provisioning can lead to over-committed storage, causing space to run out unexpectedly.

    • Snapshot Growth: Uncontrolled growth of VM snapshots can consume significant space.

  • Compatibility and Versioning

    • Incompatibility: Issues can arise when using different versions of VMFS, especially when migrating VMs between environments with different VMFS versions.

    • Upgrade Problems: Problems may occur during VMFS version upgrades, potentially leading to data inaccessibility.

  • Connectivity Issues

    • Storage Path Failures: Problems with the underlying storage infrastructure (SAN/NAS) can lead to loss of connectivity to VMFS datastores.

    • Multipathing Problems: Incorrect configuration or failures in multipathing can disrupt access to storage.

  • Locking Mechanisms

    • File Locking Issues: VMFS uses file locks to prevent multiple hosts from accessing the same VM files simultaneously, which can sometimes cause problems, particularly in clustered environments.

  • Snapshot and Clone Problems

    • Stale Snapshots: Old or unused snapshots can accumulate, leading to performance degradation and space issues.

    • Clone Failures: Issues with cloning VMs can occur, often related to underlying storage problems.

  • Backup and Recovery Challenges

    • Backup Failures: Problems with backup solutions integrating with VMFS, causing backup failures.

    • Restore Issues: Difficulties in restoring VMs or datastores from backups, often due to inconsistencies or corruption.

  • Configuration Errors

    • Misconfigurations: Errors in configuring the VMFS datastore, such as incorrect block sizes or alignment issues, can lead to performance and operational problems.

  • Hardware and Firmware Issues

    • Incompatibility: Firmware or driver issues with storage hardware can affect VMFS stability and performance.

    • Failures: Physical hardware failures, such as disk or RAID controller failures, can lead to data loss or corruption.

  • Environmental Factors

    • Power Outages: Sudden power losses can lead to file system corruption.

    • Network Failures: Issues in the network infrastructure can affect access to networked storage.



Solutions Using VMFS Recovery



  • Corruption

    • Metadata Corruption: Use VMFS Recovery to scan the damaged VMFS datastore. The tool can recover lost or corrupted metadata, restoring access to the data.

    • File System Corruption: VMFS Recovery can scan the file system for corruption, repair logical structures, and recover inaccessible files.

  • Performance Issues

    • Fragmentation: While VMFS Recovery is primarily a data recovery tool, it can help by recovering fragmented files, allowing you to move data to a more optimized storage setup.

    • I/O Contention: Identify performance issues by recovering data and analyzing usage patterns. Once data is recovered, consider restructuring your storage to reduce I/O contention.

  • Capacity and Space Management

    • Overprovisioning: Recover data from over-provisioned datastores, then re-evaluate and adjust your provisioning strategy.

    • Snapshot Growth: Use VMFS Recovery to recover data from snapshots, then delete stale snapshots to free up space.

  • Compatibility and Versioning

    • Incompatibility: Recover VMs from datastores with compatibility issues, allowing you to migrate them to environments with compatible VMFS versions.

    • Upgrade Problems: If an upgrade leads to data inaccessibility, use VMFS Recovery to recover the affected data and ensure it is properly backed up before retrying the upgrade.

  • Connectivity Issues

    • Storage Path Failures: Recover data from datastores that have become inaccessible due to path failures. Once data is recovered, address the underlying connectivity issues.

    • Multipathing Problems: Use VMFS Recovery to access data from affected datastores, then reconfigure multipathing to ensure stable access.

  • Locking Mechanisms

    • File Locking Issues: VMFS Recovery can help recover files that are locked or otherwise inaccessible, allowing you to resolve locking conflicts and restore normal operation.

  • Snapshot and Clone Problems

    • Stale Snapshots: Recover data from snapshots using VMFS Recovery, allowing you to consolidate or delete unnecessary snapshots.

    • Clone Failures: If cloning fails, use VMFS Recovery to retrieve the VM data, then attempt the cloning process again with the recovered data.

  • Backup and Recovery Challenges

    • Backup Failures: Recover data from datastores where backups have failed, ensuring you have access to the latest data.

    • Restore Issues: Use VMFS Recovery to restore data from damaged backups or recover directly from the affected datastore.

  • Configuration Errors

    • Misconfigurations: Recover data from misconfigured datastores, then reconfigure the datastore with correct settings to prevent future issues.

  • Hardware and Firmware Issues

    • Incompatibility: Use VMFS Recovery to access and recover data from datastores affected by hardware or firmware incompatibilities.

    • Failures: Recover data from disks or RAID arrays that have experienced hardware failures, allowing you to replace the failed hardware without data loss.

  • Environmental Factors

    • Power Outages: Recover data from VMFS datastores affected by sudden power losses, ensuring data integrity.

    • Network Failures: Use VMFS Recovery to access data from networked storage affected by network issues, ensuring continuous availability.



Steps to Use VMFS Recovery:



  1. 1. Install VMFS Recovery: Download and install the VMFS Recovery tool on a compatible system.

  2. 2. Scan the Affected VMFS Datastore: Launch the software and select the damaged or corrupted VMFS datastore. Initiate a scan to identify recoverable data.

  3. 3. Analyze the Results: Once the scan is complete, review the list of recoverable files and metadata.

  4. 4. Preview the recovered data: Mount recovered VMDK files as a virtual disk to browse guest OS contents and check the integrity of the recovered files.

  5. 5. Recover Data: Choose the files or entire VMs to recover. Specify a destination for the recovered data, which can be a different datastore or external storage.

  6. 6. Verify Integrity: After recovery, verify the integrity of the recovered data. Check VMs for consistency and functionality.

After recovery, verify the integrity of the recovered data. Check VMs for consistency and functionality.



Useful articles and Tutorials







Return to contents