Initial copy response time is response time associated with multiple operations of initial copying. Determine initial copy response time by using the following formula:
initial-copy-response-time (ms) = (1 [MB]/line-speed-between-primary-and-secondary-storage-systems [MB/ms]) x (initial-copy-speed/4) x (maximum-number-of-initial-copy-volumes/number-of-lines-between-primary-and-secondary-storage-systems)
If you connect the primary and secondary storage systems without using a channel extender, specify one of the following values for line-speed-between-primary-and-secondary-storage-systems depending on the link speed:
- When the link speed of the cable is 2 Gbps: 0.17 MB/ms
- When the link speed of the cable is 4 Gbps: 0.34 MB/ms
- When the link speed of the cable is 8 Gbps: 0.68 MB/ms
- When the link speed of the cable is 16 Gbps: 1.36 MB/ms
- When the link speed of the cable is 32 Gbps: 2.72 MB/ms
- When the link speed of the cable is 64 Gbps: 5.44 MB/ms
Substitute one of the following values for initial-copy-speed in the formula.
- When only an initial copy operation is performed and the copy speed specified at pair creation is 1 to 4: Use the copy speed you specified at pair creation.
- When only an initial copy operation is performed and the copy speed specified at pair creation is 5 to 15: Use 4.
- When an initial copy operation and an update copy operation is performed simultaneously and the copy speed specified at pair creation is 1 or 2: Use the copy speed you specified at pair creation.
- When an initial copy operation and an update copy operation is performed simultaneously and the copy speed specified at pair creation is 3 to 15: Use 2.
Use the setting for individual storage systems as maximum-number-of-initial-copy-volumes. The default is 64.
If the result of maximum-number-of-initial-copy-volumes/number-of-lines-between-primary-and-secondary-storage-systems is 16 or greater, use 16.
The following table lists some examples of values you might have for remote connection options.
| Round trip time (ms) | Line speed between primary and secondary storage systems (MB/ms) | Number of lines between primary and secondary storage systems | Initial copy speed | Maximum number of initial copy volumes | Round-trip response time (ms) |
|---|---|---|---|---|---|
| 0 | 0.1 | 4 | 4 | 64 | 160 |
| 30 | 0.1 | 4 | 4 | 64 | 220 |
| 100 | 0.1 | 4 | 4 | 64 | 360 |