On Thu, 2009-02-12 at 12:40 +0100, Tomasz Chmielewski wrote: > Is it somehow possible to limit OpenSSH client's bandwidth? > > Today I was copying data (whole block devices) over internet > with: > > dd if=/dev/san10/xen1 | bzip2 -9 | ssh 192.168.15.46 "bzip2 -d | dd of=/dev/san18/xen1" > > > It worked fine, but the latency of other connections was horrible, > because the above connection ate almost all bandwidth available. > > > scp has this option: > > -l limit > Limits the used bandwidth, specified in Kbit/s. > > But it looks that it's not available to ssh. > > I wouldn't like to use 3rd party programs or system settings, > because they are not portable, sometimes require root privileges > and are just additional burden for a one-off task. > > SSH has always been meant for interactive shell - not file copying. therefore, the -l (or similar) flag has no point there (unless your are piping file copy operations through SSH) :D Other problem is that SSH (being meant for interactive shell) sets the TOS (type of service) bits to 'minimize delay'. SCP on contrary does not do this, so even not throttled scp (full bandwidth) won't spoil your concurrent ssh interactivity, because default qdisc attached to each device on linux - pfifo_fast honours TOS bits - will send out SSH traffic first, let the scp traffic queue. M. This e-mail message may contain confidential and/or privileged information. If you are not an addressee or otherwise authorized to receive this message, you should not use, copy, disclose or take any action based on this e-mail or any information contained in the message. If you have received this material in error, please advise the sender immediately by reply e-mail and delete this message. Thank you. Allinea Software and Streamline Computing are trading divisions of Concurrent Thinking Limited: Registered in England and Wales No: 03913912 Registered Address: The Innovation Centre, Warwick Technology Park, Gallows Hill, Warwick, CV34 6UW, United Kingdom
