Abstract: Disclosed are systems, computer-readable mediums, and methods for incremental block level backup. An initial backup of a volume is created at a backup server, where creating the initial backup includes retrieving an original metadata file from a metadata server, and retrieving a copy of all data of the volume based on the original metadata file. A first incremental backup of the volume is then created at the backup server, where creating the first incremental backup includes retrieving a first metadata file, where the first metadata file was created separately from the original metadata file. A block identifier of the first metadata file is compared to a corresponding block identifier of the original metadata file to determine a difference between the first and original block identifiers, and a copy of a changed data block of the volume is retrieved based on the comparison of the first and original block identifiers.

Abstract: Detecting modifications to a storage that occur in an alternate operating environment. In one example embodiment, a method for detecting modifications to a storage that occur in an alternate operating environment may include tracking, in a modify map, modifications to a storage that occur during operation of a primary operating environment, identifying a first most recent transaction identifier in a journal of a file system of the storage prior to closing of the storage by the primary operating environment, upon opening of the storage by the primary operating environment, identifying a second most recent transaction identifier in the journal, determining that the second most recent transaction identifier does not match the first most recent transaction identifier, concluding that the storage was modified in an alternate operating environment between the closing and the opening of the storage by the primary operating environment, and invalidating the modify map.

Abstract: Storing and retrieving files based on hashes for the files. One method for storing files includes: identifying a file; identifying a hash calculated based on the file; renaming the file based on the hash based on the file; and storing the file in a particular location based on the hash calculated based on the file. Another method for retrieving files includes: identifying a hash for a given file; using the hash, traversing a hierarchical file structure to find a location where the given file should be stored; determining that the file is at the location; and as a result, retrieving the file.