Hi all,

I'm trying to do some web server benchmarking to get an idea of various configurations and their relative performance for an app. I have two linode's set up (set up the second one basically to get fast networking to really be able to test the server), but found that the throughput was topping out at around 45 kbytes/sec. So I enabled private networking on both linode's and followed the config guide to do the static IP allocation.

For both linodes I've configured /etc/network/interfaces to have eth0 be the public IP, and eth0:0 the private IP. I added the options rotate to /etc/resolv.conf as well, then restarted networking (and of course, restarted both servers after enabling private networking).

However when I test this with my private IP's I get:

------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  4] local 192.168.166.xxx port 5001 connected with 192.168.166.xxx port 32895
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-10.2 sec  54.9 MBytes  45.3 Mbits/sec

I can't imagine this is actually using the private network as 45 Mbit/sec in a datacenter would be ridiculous. Is there something else I need to do, or something to check?[/code]

By default the virtual ethernet interface of a Linode is bandwidth limited to 50Mbps outbound (inbound doesn't appear to have a limit). This is on the virtual interface in general, so affects both public and private address space.

Not sure why you'd only be getting 45Kbytes/s on the public interface. You may not hit 50Mbps easily with just one sink depending on latency, but that seems really low.

You can open a support ticket to have the limit increased (to 100Mbps), but in my experience are asked to explain your need and to demonstrate that you can utilize the higher rate.

-- David

Are you sure about that? 50Mb is largely what you can get through the public interface no? I can't imagine linode would offer private networking with no greater speed than the outgoing data center pipe, it would make doing any sort of clustering or load balancing much less useful...

I also found this post from just a few days ago and he managed to get over 1 Gb per second on the private network...

http://alittletothewright.com/index.php/2011/02/linode-private-network-speed-tests/

From the page you cited:

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One of the main reasons to use private networking is not for speed between servers, it is to reduce the amount of bandwidth used when talking between servers in the same datacenter.

If you need it to be faster, you can get the limit raised.

When I was migrating to a new Linode, I filed a ticket, and they bumped the limit to 150Mbps. I updated the ticket when I was done to get it dropped back down to 50Mbps.