Chapter 11. Advanced Copy Services 457
Cleaning Rate
The data rate at which data is copied from the target of the mapping being stopped to the next 
oldest target is determined by the cleaning rate. This property of the FlashCopy mapping and 
can be changed dynamically. It is measured like the copyrate property, but both properties are 
independent. Table 11-5 lists the relationship of the cleaning rate values to the attempted 
number of grains to be split per second.
Table 11-5   Cleaning rate values
11.1.12  Reverse FlashCopy
Reverse FlashCopy enables FlashCopy targets to become restore points for the source 
without breaking the FlashCopy mapping, and without having to wait for the original copy 
operation to complete. A FlashCopy source supports multiple targets (up to 256), and 
therefore multiple rollback points.
A key advantage of the IBM Spectrum Virtualize Multiple Target Reverse FlashCopy function 
is that the reverse FlashCopy does not destroy the original target. This feature enables 
processes that are using the target, such as a tape backup or tests, to continue uninterrupted.
IBM Spectrum Virtualize also provides the ability to create an optional copy of the source 
volume to be made before the reverse copy operation starts. This ability to restore back to the 
original source data can be useful for diagnostic purposes.
User-specified copy rate attribute 
value 
Data 
copied/sec
256 KB 
grains/sec
64 KB 
grains/sec
1 - 10 128 KiB 0.5 2
11 - 20 256 KiB 1 4
21 - 30 512 KiB 2 8
31 - 40 1 MiB 4 16
41 - 50 2 MiB 8 32
51 - 60 4 MiB 16 64
61 - 70 8 MiB 32 128
71 - 80 16 MiB 64 256
81 - 90 32 MiB 128 512
91 - 100 64 MiB 256 1024
101 - 110 128 MiB 512 2048
111 - 120 256 MiB 1024 4096
121 - 130 512 MiB 2048 8192
131 - 140 1 GiB 4096 16384
141 - 150 2 GiB 8192 32768