On Wed, Jan 27, 2010 at 3:27 PM, Matt Zagrabelny <mzagrabe@xxxxxxxxx> wrote: > On Wed, 2010-01-27 at 11:45 +0100, Ketil Froyn wrote: >> Hi, >> >> I am based in Norway, and I'm benchmarking upload and download speeds >> to and from a US site (Rackspace Cloud Files). I'm on a 1Gbit link >> with a 100Mbit firewall limiting my speeds, but I routinely see both >> uploads and downloads at 20Mbit, and spikes up to 50Mbit. Ping latency >> between my site and the US site is about 170ms. >> >> The speeds I'm seeing for single large file transfers when benchmarking are: >> >> uploads: 90kb/s - 140kb/s >> downloads: 450kb/s - 500kb/s > > So are you seeing 20Mb/s or 90 - 140 and 450 - 500 kb/s ? I regularly see 20Mb/s on downloads from outside our network by customers of the service I'm running. 90-140kb/s is the speed I get when uploading files to Rackspace, and 450-500 when downloading from Rackspace. > How many hops away are you from the destination system? Traceroute shows 14 hops before I get * * * after 3 hops in Rackspace's own net. > Are you sure there is no shaping, throttling, or other contention > (besides the firewall) between your system and the destination? There's none on our side by us or our ISP. I asked Rackspace, they said they allow much faster transfers than what I see. > Use iperf (aptitude install iperf) to saturate the link. You can send > both TCP and UDP packets/streams. I can't test that against Rackspace, but since I have access to a virtual host in the US anyway, I can test against that instead. It has approx 130ms rtt. Testing, I see bandwidth numbers varying from 682Kbit/s to 1.59Mbit/s. I got some even lower numbers when I tried to increase the window size. I've also noticed some other things: 1. ping shows a ~1% packet loss (2 packets out of 120 missing). 2. scp transfers start at about 360kb/s, and then fall, completing a file at an average of about 85kb/s (680Kbit/s) 3. running 2 scp in parallell, they also started faster and then fell, ending at about 82kb/s each (~1.3Mbit/s total) 4. running 4 scp in parallell, they got an average of about 78kb/s each, and gave a total of ~2.4Mbit/s transferred So the network appears to be able to handle more data transferred than a single transfer can handle, so I guess it should be able to tune this somehow? Or do I just need to run many transfers in parallel? (I may have been inaccurate with my use of kb/Kbit, but I mean kilobyte and kilobit, respectively, *1024 in both cases.) Regards, Ketil -- To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
