What is the relationship between blocks and files?
The so-called block refers to the disk block. The disk block is the smallest logical unit for the file system to manage the disk (partition) (Windows is called a cluster, which has a similar meaning to "block"). It is also the smallest unit for the operating system and software to use the disk. It is a logical unit. the concept of. The smallest unit of real disk reading and writing is the sector, and the reading and writing of disk blocks are eventually converted into sector operations. Usually, a file is stored in several blocks, and one block corresponds to several physical sectors.
What is block migration?
Block migration refers to migrating based on the file system block (Block), so even if the network is interrupted, the corresponding block only needs to be retransmitted when the network recovers, and when the file is modified during migration, it only needs to be synchronized It is enough to modify the corresponding block without synchronizing all the blocks contained in the file.
What is file migration?
File migration uses tools or TAR commands and SSH or other channels for remote copying. Therefore, as long as there are changes in file compression or the network is interrupted during migration, the migration will fail. And during incremental data synchronization, as long as the file changes, the file needs to be synchronized, and all blocks corresponding to the file will be reselected. Synchronization efficiency is low.