How snapshot data is stored

The Copy-After-Write (CAW) method is the default method of storing snapshot data. When the write pending rate in cache memory is 60% or higher, the Copy-On-Write (COW) method is used. In the CAW method, writing the P-VOL snapshot data changes the status to “write completion”. In the COW method, storing the P-VOL snapshot data changes the status to “write completion”.

The CAW method wait time is shorter than that of the COW method.