Time Estimating Factors
Establish how much data is on the hard drive to be cloned. This is the single most critical factor in estimating the time to clone a hard drive. It is also to crucial to determine the method that will be used to clone the drive. For example, in a scenario where one drive will be cloned to multiple systems, as in the case of an OEM system builder, this initially becomes a two step process. The original drive will be cloned to a data repository where it will be saved as an image, and then it will be cloned onto the bare drive from there. Alternately, in a computer upgrade scenario, where the two hard drives are located in the same computer, the cloning process will be direct, where the first drive will be cloned directly to the second drive, with no intermediate step being required. The third consideration is the type of hard drives themselves, and to lesser extent, the computer system's specifications. Remember, in situations where an older drive technology is being used to clone to a newer drive, in a direct, drive to drive transfer, the speed of the older drive will be the determining factor.
Drive Transfer Specifications
When reviewing drive transfer rates, keep in mind that the rates quoted are "burst" rates, and not sustained transfer rates. An ATA-100 IDE drive might claim that it can transfer data at 100MBps (Megabytes per second) but it will not be able to move a gigabyte's worth of data at this speed in the real world. This reality holds true for the newer high speed SATA drives which claim to be able to transfer 300MBps (Megabytes per second), but the real transfer rates that should be used to calculate a clone process should be lowered to roughly one half of that speed.
Calculating Cloning Time
Calculating Cloning Time:
For this example, we will use an ATA-100 drive which has 100GB of data stored on it to be cloned. To estimate the time to clone this drive, the calculations would look like this:
100 Gigabytes = 100,000 Megabytes 100,000 Megabytes/100 MBps = 1,000 seconds 1,000 seconds/60 = 17 minutes (Please note – this time needs to be doubled to arrive at an optimistic number based on the fact that the ATA-100 drive will not be able to deliver 100MBps transfer rates.)
The calculations provided above will require the drive transfer rates that the drives you are cloning to be substituted in place of the values provided.