On Wed, Feb 27, 2013 at 03:50:53PM +0000, Dietmar Maurer wrote: > > NBD enables interprocess communication - any form of IPC requires a protocol > > and NBD is quite a trivial one. What is a simpler way of talking to a > > backup > > server? > > Unfortunately, NBD add considerable overheads. I guess the socket > communications copies data. > This is really unnecessary if I can write directly to the output stream.
The disk is the bottleneck, not memory bandwidth. Hard disks only do 10-100 MB/sec and SSDs only do a couple 100 MB/sec. Memory copy is insignificant compared to the I/O activity required to copy out the entire disk image, not to mention delaying guest writes until we read the original data from the disk. Unless there's a concrete performance problem here this is premature optimization. Stefan
