# dd if=/dev/zero of=guest bs=1G count=14 14+0 records in 14+0 records out 15032385536 bytes (15 GB) copied, 658.655 s, 22.8 MB/s 14 * 1024 * 1024 * 1024 = 15032385536 So the correct number of bytes are getting written. 15GB in the initial statement from dd is wrong.
Thanks for report, but it's not a bug. As you could check on http://physics.nist.gov/cuu/Units/binary.html for quiet a long time exists unification of binary units. Command dd should show 14G (or better 14GiB) or 15GB in this case, but it doesn't matter which one will be shown. It is described in info pages(dd, Note: Block size::) and help page of dd command. Citation from dd's help page: "BLOCKS and BYTES may be followed by the following multiplicative suffixes: xM M, c 1, w 2, b 512, kB 1000, K 1024, MB 1000*1000, M 1024*1024, GB 1000*1000*1000, G 1024*1024*1024, and so on for T, P, E, Z, Y." Closing NOTABUG.