fatvm – Share how to extend virtual disks

Most of us who have copied large files over the Internet (or even within the company’s network for that matter) have been surprised by the amount of time it takes. We dont have a mapping in our mind that can relate the network bandwidth in Mbps with the size of the file to be transferred (GB). I found a nifty file transfer time calculator on the Internet and computed the effective transfer rate for several different bandwidth options by subtracting the signal overhead and an average 5% Layer 4 overhead from the rated capacity. The table below shows the expected transfer times for different network bandwidths, your mileage will vary with the Internet/internal network traffic at your site.

The timings for T1 correlate very closely with my experience of transferring VM’s between my machine and ec2 when I am the sole user. It takes me over half a day to transfer a 10Gb VM and this is really wearing me down.

The chronic problem is how to reduce the time taken to copy VM’s to a remote datacanter, either one owned by your company or a cloud provider, over your company’s private network or on the Internet. Neitwork bandwidth will always remain a gating issue for most of us who are developers.