On Fri, 27 Aug 2010, Mr. MailingLists wrote: > dd if=/dev/random of=175MBFile bs=1024k count=175 > scp 175MBFile chickenclucker:~/ > 175MBFile 100% 175MB 35.0MB/s 00:05 > scp -C 175MBFile chickenclucker:~/ > 175MBFile 100% 175MB 9.7MB/s 00:18 > > time gzip -c 175MBFile > 175MBFile.gz > 12.513s > 183500800 Aug 27 11:58 175MBFile > 183556808 Aug 27 11:58 175MBFile.gz > > dd if=/dev/zero of=175MBFile bs=1024k count=175 > scp 175MBFile chickenclucker:~/ > 175MBFile 100% 175MB 35.0MB/s 00:05 > scp -C 175MBFile chickenclucker:~/ > 175MBFile 100% 175MB 35.0MB/s 00:05 > > time gzip -c 175MBFile > 175MBFile.gz > 0m2.552s > 183500800 Aug 27 12:03 175MBFile > 178393 Aug 27 12:03 175MBFile.gz > > Interesting results and I learned something new today (I friggan love when that happens!). Me too because I don't think I've ever used dd. Related question: I'm pretty sure there's a way to pipe the stdout to ssh and have it transfer to /dev/null on the other end so that you can compare speeds for arbitrarily large transfers without making files. Anyone know? dd if=/dev/zero bs=1024k count=4000 | ssh ... I think if you were to make your file much bigger, maybe several gigabytes, you'd see a big benefit of compression. It's not a realistic example though because your file is just the same null character repeated a gazillion times. So, on your network, running at 250 Mbps or so, you probably never want to use compression. Mike