A method implemented at least in part by a computer, the method comprising: determining whether to backup a file (200; 300), the file including at least a content segment having content data and a metadata segment having metadata that describes the content data, the determining including: computing a metadata hash of at least a portion of the metadata segment of the file; computing a content hash of at least a portion of the content segment of the file; determining whether the metadata has changed based at least in part on whether the metadata hash is equal to a previously computed metadata hash; and determining whether the content data has changed based at least in part on whether the content hash is equal to a previously computed content hash; and selectively initiating backup of the file, the selective initiation including: in response to determining that the content segment has not changed and that the metadata segment has changed, not initiating backup of the file; and in response to determining that the content segment has changed and that the metadata segment has not changed, initiating backup of the file. determining whether to backup a file (200; 300), the file including at least a content segment having content data and a metadata segment having metadata that describes the content data, the determining including: computing a metadata hash of at least a portion of the metadata segment of the file; computing a content hash of at least a portion of the content segment of the file; determining whether the metadata has changed based at least in part on whether the metadata hash is equal to a previously computed metadata hash; and determining whether the content data has changed based at least in part on whether the content hash is equal to a previously computed content hash; and selectively initiating backup of the file, the selective initiation including: in response to determining that the content segment has not changed and that the metadata segment has changed, not initiating backup of the file; and in response to determining that the content segment has changed and that the metadata segment has not changed, initiating backup of the file. computing a metadata hash of at least a portion of the metadata segment of the file; computing a content hash of at least a portion of the content segment of the file; determining whether the metadata has changed based at least in part on whether the metadata hash is equal to a previously computed metadata hash; and determining whether the content data has changed based at least in part on whether the content hash is equal to a previously computed content hash; and selectively initiating backup of the file, the selective initiation including: in response to determining that the content segment has not changed and that the metadata segment has changed, not initiating backup of the file; and in response to determining that the content segment has changed and that the metadata segment has not changed, initiating backup of the file. in response to determining that the content segment has not changed and that the metadata segment has changed, not initiating backup of the file; and in response to determining that the content segment has changed and that the metadata segment has not changed, initiating backup of the file.