Agnello George wrote:
Hi I have small query, all our server are centos based 5 and 5.2 . We are looking ofr a tool to that measure packet loss. we have servers in two IDC's bothin the US and we are trying to download a 2gb file from the internet. Some server are able to download the file at a higher b/w rate in one IDC ...while servers at he the other IDC download the same file at a lowe b/w rate . Is ther any tool to measure packet losses. Thanks a lot !
ping.
Also latency is much more likey a culprit of your bandwidth issues rather than packet loss. Use ping or traceroute to measure the latency from the sources to the destination(s). I have one of my sites upload roughly 550GB of data per day to another site that is on the other side of the country, fortunately the data comes from 40+ servers so running them all in parallel I can get the data pretty fast(about 350Mbit). Running each server one at a time I tend to get roughly 7Mbit/s a pop(each side has a gigabit internet link).
In order to improve throughput I'm using rsync over HPNSSH, which does some basic TCP magic to improve throughput over higher latency connections - http://www.psc.edu/networking/projects/hpn-ssh/
Interestingly enough on downloads I get higher performance, with 10 connections I can get 250Mbit, whereas on uploads I get about 70mbit, just came across that a couple of days ago. Perhaps for some reason HPNSSH is not as optimized for uploads(?). In any case I work around it with multiple threads/processes since I'm dealing with roughly 150k files of various sizes per day.
Worst case split the file up on the other side and transfer it in parallel and reconstruct it locally.
nate