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Virtual machine is corrupted after it is restored over the SAN transport mode (2055682)

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After restoring a virtual machine over the SAN transport mode, you experience either of these symptoms:
  • The virtual machine fails to boot
  • The virtual machine boots successfully, but some files or registry settings are missing or corrupted


When using SAN transport to restore a thick lazy zeroed disk, if the restore buffer size is larger than the block size of the datastore, the lazy zero flag gets cleared for the first block only. Data that is written to the disk for second and later blocks are ignored on subsequent reads because the lazy zero flags for these blocks are not cleared.


This issue has been fixed in VDDK 5.1 and VDDK 5.0 U3.
To work around this issue when you do not want to upgrade, in the backup application, ensure that these requirements are met:
  • The restore buffer size must be lesser than or equal to the block size of the datastore. For example, when using a 1MB datastore block size, the write buffer size must be lesser than or equal to 1MB.
  • The write should not cross the VMDK block boundary. If the write crosses the VMDK block boundary, the SAN write operation fails to write the data that is beyond the block boundary.

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