how to control the rebalance time ?

Hi,

We have an half rack ExadataX2-2 with cells of high capacity disks.There are 3 diskgroup ,and each cell have about 12TB used space. We moved out two cells one by one.

 When moved first cell from the rack, the rebalance time is about 5 hours and 27 minitues with power_limit 64.

For reduce the rebalance time, we increase the power_limit to 256. While it spend about 6 hours and 19 minitus for the movement of second cells.

Here's the caculation :

First time:   12TB *1024 / 5.27/3600 = 0.647GB/s

second time: 14TB *1024 /6.19/3600 =0.643 GB/s

In Exadata X2-2 datasheet, the bandwith for half rack is 7GB/s,means each cell have 1GB/s bandwith. so the IO does reach the bottlnect in the operation.