How do I recover data from a virtual machine?

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How do I recover data from a virtual machine

Recovering lost or deleted data from a virtual machine can be challenging, but is often possible with the right tools and techniques. Virtual machines run as files on a physical host computer, so even if the virtual machine is corrupted or deleted, the virtual drive files may still be recoverable from the host system.

What causes data loss on a virtual machine?

There are several common causes of data loss on virtual machines:

  • Accidental deletion – Deleting the wrong virtual machine or virtual disk file.
  • Corruption – File corruption of the virtual disks from unexpected shutdowns, power loss, or storage failures.
  • Ransomware infection – Ransomware encrypting the virtual disks, rendering the data inaccessible.
  • Storage failure – Underlying storage failure or disconnect causing virtual disks to become unavailable.
  • Insufficient backups – Lack of recent valid backups to restore from.

How to recover deleted virtual machines

If you have accidentally deleted a virtual machine, the first step is to check if it is still available in the recycle bin or trash folder. On Windows, go to Recycle Bin and look for .vmdk, .vhd, or other virtual disk files. On Mac and Linux, check the trash folder for these files. If found, you can attempt to restore the deleted virtual machine by moving the files back to the original location.

If the deleted virtual machine is not in the recycle bin, you may still be able to recover it using file recovery software as long as the sectors containing the virtual disk files have not been overwritten with new data. Some popular file recovery tools include:

  • Recuva – Works well for recovering deleted files on Windows.
  • TestDisk – Open source tool for recovering deleted partitions and data.
  • PhotoRec – Recovers various file types based on file signatures.
  • R-Studio – Advanced commercial recovery software for Windows and Mac.

To recover a deleted virtual machine with recovery software:

  1. Download and install a file recovery program onto the physical host computer.
  2. Scan the drive containing the virtual machine files.
  3. Select the .vmdk, .vhd or other related files detected by the software.
  4. Specify a new folder to recover the files to.
  5. Open the recovered virtual disk files in a virtualization platform like VMware or VirtualBox.

Recovering from virtual disk corruption

If a virtual machine’s disk files have become corrupted or unreadable, there are several approaches to try recovering the data:

  • Virtualization platform tools – Hypervisors like VMware and VirtualBox include utilities for repairing and compacting virtual disks to fix file corruption issues.
  • Disk repair software – Utilities like WinDFT and chkdsk can scan corrupted filesystems and repair logical file system errors.
  • Data recovery software – If the file system is badly corrupted, advanced data recovery software may be able to extract data based on the raw disk sectors.
  • Backup copies – Restore corrupted virtual disks from clean backups or snapshots to recover virtual machines.

When corruption occurs, it’s critical to avoid anything that may overwrite or alter the original corrupted virtual disk files before attempting recovery. Powering off the virtual machine and making a copy of the affected disk files is recommended.

Recovering encrypted or ransomware infected VMs

Ransomware is one of the top threats facing virtualized environments today. If a VM becomes infected and the disks encrypted, this can lead to total data loss if action is not quickly taken.

The best protection against ransomware is proactive measures like isolating and backing up VMs. But if a VM does fall victim to ransomware encryption, options include:

  • Isolate and shut down the VM – This can prevent further encryption and damage.
  • Restore from backups – Having dependable VM backups or replicas allows restoring to an earlier unaffected state.
  • Try brute forcing the encryption – This is unlikely, but security experts may attempt decryption on high value targets.
  • Wipe and rebuild the VM – If data is expendable, rebuilding the VM clean may be easiest.
  • Pay the ransom – This is controversial and no guarantee of recovery.

Virtualization admins should take ransomware seriously and implement layered defenses across hypervisors, guest VMs, backups, and overall security practices.

Recovering from storage failures

Since virtual machines rely on files residing on physical storage media, failures at the storage level can make VMs inaccessible. Some options when dealing with failed or disconnected storage include:

  • Replace or repair failed hardware – Fixing failed hard drives, controllers, HBAs may allow reconnecting VM storage.
  • Access storage directly – Attaching failed storage directly to another machine for recovery.
  • VM replication – Leverage features like vSphere HA or Hyper-V Replica to start replica VMs.
  • Backups – Restore VMs and data from backups unaffected by storage issues.

The key when troubleshooting VM storage problems is speed – the faster failed storage can be repaired or replaced, the higher chance of minimizing data loss and VM downtime.

Using backups to restore VMs

Performing regular backups that are stored offline is one of the best defenses against data loss from virtual infrastructure. Backups provide the ability to restore deleted or corrupted VMs and data from a known good state.

Types of VM backups include:

  • Full backups – Captures the entire VM state at a point in time.
  • Incremental backups – Only captures changes since the last backup.
  • Differential backups – Captures all changes since the last full backup.
  • Reverse Incremental backups – Starts full and becomes progressively smaller.

Key considerations for effective VM backup practices:

  • Use reputable enterprise backup software designed for virtual infrastructure.
  • Follow the 3-2-1 rule – 3 copies, 2 local and 1 offsite.
  • Test restores periodically to validate recoverability.
  • Enable compression and deduplication to optimize storage efficiency.
  • Backup entire VMs as well as guest OS files for maximum flexibility.

With solid backups in place, VMs and data can quickly be restored to handle events like storage failures, ransomware, accidental deletions, and more. Tested backups are your last line of defense.

Third party data recovery services

In cases of catastrophic virtual machine failure or data loss, where in-house efforts have been fully exhausted, a last resort option is to turn to a professional data recovery company. They offer services like:

  • Clean room recovery – Rebuild RAID arrays and access data at disk level.
  • Advanced forensic recovery – Utilize specialized techniques and hardware.
  • Full disk imaging – Image drives byte-for-byte for safe examination.
  • File carving – Pull raw files from unallocated space based on headers, footers, internal structures.
  • Database and email repair – Rebuild corrupted databases, extract emails.

The benefits of third party recovery include access to proprietary tools and methods your team may lack. But drawbacks are high costs scaling to thousands of dollars, and no guarantee of success. Weigh the value of lost VM data vs recovery expenses.

Prevention checklist

While options exist for recovering lost or corrupted VMs, prevention is always preferable to cure. Steps to help avoid issues proactively:

  • Use enterprise virtualization platforms – VMware vSphere, Microsoft Hyper-V, etc. Consumer tools like VirtualBox have fewer safeguards.
  • Follow vendor best practices for VM configuration, host resources, uptime, etc.
  • Isolate and dedicate storage for VMs – Don’t store other data on VM volumes.
  • Use clustered shared storage like SAN, NAS for VMs – Enables HA and migration.
  • Perform regular VM backups to tested media – Maintain multiple generations.
  • Enable replication features like vSphere HA and Fault Tolerance.
  • Protect VMs with antivirus scanning, firewalls, and security hardening.
  • Monitor infrastructure health with management tools.

Building resilience and redundancy into virtual infrastructure is key to avoiding catastrophic data loss events. An ounce of prevention is worth a pound of cure.

Conclusion

While loss or corruption of VM data is never desired, it is an unfortunate risk that must be planned for. By understanding the common causes of VM data loss, methods for recovery, and sound prevention practices, IT teams can be well equipped to deal with VM disasters and minimize business impact when issues occur.

The keys are preparation through policies like backup and replication, rapid response when incidents happen, and leveraging the various tools and techniques outlined here for recovering deleted, corrupted, encrypted or otherwise inaccessible VM data and restoring services.