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Corrupted vmdk files?

Some of the Support Requests our Support Engineers deal with for both VMware Fusion and Workstation are data loss and vmdk (virtual hard-drive) issues with customer virtual machines. Issues vary from broken snapshot chains, deleted child or parent vmdk files, corrupt vmdk files, or a file level corruption for virtual machine files. Corruption is not taken lightly by anyone who experiences it, and as well they shouldn’t. It’s a punishing event when it happens.

In some of these Support Requests, we are unable to recover the lost files for the end user; files have been permanently deleted or corrupted.

We continue to discover that users have the (misguided) perception that taking regular snapshots can help them if data loss occurs. Unfortunately, this could not be further from the truth. Snapshots files are located on your physical machine’s physical disk and are subject to the same risk of file level corruption which can happen to any file or folder on a physical machine from some unseen mishap.

So, what is the best way to insure the integrity of your virtual machines? In one word, Backups. Just as in the physical realm, backups remain the number one protection against unforseen corruption.

The following backup procedures and best practices for virtual machines is documented in the following Knowledgebase articles.

We cannot overstate this simple piece of advice. Schedule regular backups of your important virtual machines so that you have a recovery path available.

4 thoughts on “Corrupted vmdk files?

  1. André Pett

    I absolutele agree. It can’t be said often enough: “Snapshots are NO backups!”
    Although the following KB article is not written for hosted VMware products, it’s definitely worth reading.
    “Understanding virtual machine snapshots in VMware ESXi and ESX” (http://kb.vmware.com/kb/1015180)

  2. Stu

    It would help very much if there was an option to put snapshots on a different drive/network share, in all VMware software that provides snapshots.

    1. Wil van Antwerpen

      @stu, actually that would not help at all! VMware vmdk snapshots are Copy On Write. Meaning that the snapshot is absolutely useless without your original data. Saving the snapshot to another disk while loosing the base disk, just makes you have a bunch of semi-random data. Without the base disk you cannot recreate the original.

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