462 Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1
With this configuration, use a copyrate equal to 0 only. In this state, the virtual capacity of the 
target volume is identical to the capacity of the source volume, but the real capacity (the one 
that is used on the storage system) is lower, as shown on Figure 11-15. The real size of the 
target volume increases with writes that are performed on the source volume, on not already 
copied grains. Eventually, if the entire source volume is written (unlikely), the real capacity of 
the target volume is identical to the source’s volume.
Figure 11-15   Thin-provisioned target volume
Source and target thin-provisioned 
When the source and target volumes are thin-provisioned, only the data that is allocated to 
the source is copied to the target. In this configuration, the background copy option has no 
effect. 
Thin-provisioned incremental FlashCopy
The implementation of thin-provisioned volumes does not preclude the use of incremental 
FlashCopy on the same volumes. It does not make sense to have a fully allocated source 
volume and then use incremental FlashCopy (which is always a full copy the first time) to copy 
this fully allocated source volume to a thin-provisioned target volume. However, this action is 
not prohibited. 
Consider the following optional configurations:
/SM590000A thin-provisioned source volume can be copied incrementally by using FlashCopy to a 
thin-provisioned target volume. Whenever the FlashCopy is performed, only data that was 
modified is recopied to the target. If space is allocated on the target because of I/O to the 
target volume, this space is not reclaimed with subsequent FlashCopy operations.
/SM590000A fully allocated source volume can be copied incrementally by using FlashCopy to 
another fully allocated volume at the same time as it is being copied to multiple 
thin-provisioned targets (taken at separate points in time). By using this combination, a 
single full backup can be kept for recovery purposes, and the backup workload is 
separated from the production workload. At the same time, older thin-provisioned backups 
can be retained.
11.1.16  Serialization of I/O by FlashCopy
In general, the FlashCopy function in the IBM Spectrum Virtualize introduces no explicit 
serialization into the I/O path. Therefore, many concurrent I/Os are allowed to the source and 
target volumes.
Performance: The best performance is obtained when the grain size of the 
thin-provisioned volume is the same as the grain size of the FlashCopy mapping.