The difference between bitwise and file when mirroring a hard disk

[Netizen question]

When the hard disk is mirrored, I heard that there is a bitwise AND according to the file two kinds, what are the characteristics? What are the circumstances? What kind of ghost is the way?

Answer

The bitwise (In fact, sector) dump of backup work means that it has nothing to do with the file system. What the data source looks like, how big, what the goal is like, how big. Even if there are no partitions, or unrecognized partitions, or if there are errors in the partition's logical structure, they can be backed up to the target device with complete (including logical errors).

By file transfer means that you want to interpret the file system Atch, only the file to the target device. This dump program must be able to interpret the corresponding file system without extracting the file data. His data volume also depends on the sum of the source device files, and the more files there is, the more data needs to be transferred. In addition, in the form of file transfer in the source and the physical location of the target does not correspond to one by one, just like from the source disk to all files into the target device, the source disk of the file organization, physical sorting, space occupancy does not have to be the same as the target device. This kind of dump does not transfer the free space in the disk to the past.

Ghost without parameters, the default is to file the dump. Therefore, when the system occupies a larger space, ghost backup out of the larger packets. If the partition (hard disk) to partition (hard disk), but also occupy more files, spend more time. The ghost itself does not dump free space and must be a file system that ghost can recognize, so ghost does not support special file systems such as JFS, VXFS, or backup hard disk data managed by non-MBR class partition tables. When ghost without parameters, it is not suitable to be in the field of data recovery.

Typically, a bitwise dump is the most thorough way to get the most complete backups, such as backups before data recovery, backups of non-Windows systems, or special-structure backups, but requiring a larger footprint. A file dump is appropriate for bulk file backups of known file systems.