When creating a Storage Based Snapshot for a virtual machine (VM), the system will set the source virtual disks to read-only and generate a corresponding number of new disk files (i.e., snapshot space).

After the snapshot is created, all new data of the VM and modifications to the source data will be written to the newly generated snapshot space, and the corresponding relationship between the logical addresses of the source virtual disks and the snapshot space will be recorded in the mapping table.

The data write process after snapshot creation is as follows:

①The VM intends to write data and modify data "c" to data "E".

②Data "E" is redirected to the logical address "ii" in the snapshot space for writing.

③The system records the corresponding relationship between the logical addresses of the original virtual disk and the snapshot space in the mapping table, noting that the data at the original address "2" corresponds to the data at the snapshot address "ii"。