Data backup using metadata mapping
An information processing apparatus, backup method, and program product that enable efficient differential backup. In one embodiment, an information processing apparatus for files stored in a storage device includes: a metadata management unit for managing metadata of files stored in the storage device; a map generation unit for generating a map which indicates whether metadata associated with an identification value uniquely identifying a file in the storage device is present or absent; and a backup management unit for scanning the metadata to detect files that have been created, modified, or deleted since the last backup, and storing at least a data block and the metadata for a detected file in a backup storage device as backup information in association with the identification value.
1. An information processing apparatus for backing up files stored in a storage device, comprising:
a metadata management unit configured to manage metadata of files stored in the storage device;
wherein managing metadata of files comprises, for respective files, generating a respective file size, a respective last update time, a respective identification value, and a respective data block address;
a map generation unit configured to generate a map which indicates whether the metadata associated with an identification value uniquely identifying a file in the storage device is present or absent; and
a backup management unit configured to scan the metadata to detect files that have been created, modified, or deleted since a last backup, and store the map for current files, at least a data block, and the metadata for a detected file in a backup storage device as backup information in association with the identification value;
wherein the map for current files comprises an inode bitmap, wherein the data block comprises differential data for the detected file, and wherein the metadata for the detected file comprises inode information for the detected file; and
wherein the backup management unit is further configured to restore data by restoring at least the inode information for the detected file and the differential data for the detected file based on the inode bitmap having a bit set to 1 for the detected file.
2. The information processing apparatus according to claim 1 , wherein the map is a bitmap in which the presence or absence of the metadata is represented by a binary value.
3. The information processing apparatus according to claim 1 , wherein the backup storage device is a remote storage or a local storage.
4. The information processing apparatus according to claim 1 , further comprising:
a processor configured to run an application by execution of a program to create, modify, or delete files and also back up the files stored in the storage device; and
an external storage control unit configured to enable access to the storage device.
5. The information processing apparatus according to claim 4 , wherein the external storage control unit is a network adapter and the backup storage device is a remote storage connected over a network.