File level recovery using virtual machine image level backup with selective compression

摘要

Example apparatus and methods process virtual machine image level backups that may include files that are compressed and files that are not compressed. Example apparatus and methods may produce virtual machine image level backups by selectively compressing some files associated with the image while leaving other files in their uncompressed state. Example apparatus and methods may selectively recover a file or even an entire disk image from an image level backup that may include both compressed files and files that are not compressed. The file recovery or image recovery may be performed at the file level by accessing files in the image and selectively decompressing files that are compressed in the image while passing through files that are not compressed in the image. Different files in a single image may be compressed or decompressed using different techniques.

主权项

1. A method, comprising:
upon determining that an entire disk image is to be recovered from an image level backup of a virtual machine, where the image level backup may include files that are compressed and files that are not compressed:
mounting the image level backup to a target file system to produce a mounted image level backup;making a copy of the image level backup;mounting the copy in a read/write mode to a target file system to produce a mounted copy;identifying a set of files in the mounted copy that are sufficient to recover the entire disk image;for a member of the set of files, upon determining that the member is compressed, decompressing the member of the set of files in the mounted copy;synchronizing a buffer associated with the target file system to the mounted copy;unmounting the mounted copy from the target file system to produce an unmounted copy; andrecovering the entire disk image from the unmounted copy.