July 27, 2010

Rackspace Cloud - Outbound Bandwidth Caps, Network Too Slow

Have you seen the network/bandwidth caps that Rackspace places on their cloud servers?

From the Rackspace Cloud Server FAQ:

"Your Cloud Server has a bandwidth cap that is applied in relation to the size of the server. Please note that the bandwidth caps are placed on outbound bandwidth only. Inbound bandwidth is not capped."

Server SizePublic LimitServiceNet Limit
256MB10 Mbps20 Mbps
512MB20 Mbps40 Mbps
1024MB30 Mbps60 Mbps
2048MB40 Mbps80 Mbps
4096MB50 Mbps100 Mbps
8192MB60 Mbps120 Mbps
15872MB70 Mbps140 Mbps

I was going to use the Rackspace Cloud to do some performance testing of a new server. I wanted to run 2 servers in a clustered mode, replicating data to each other. My first concern was the speed of the internal network interconnects between cloud nodes.

After doing some research, I realized the bandwidth caps make it a non-starter. 20-140 Mbps private interconnects?? That's not enough. I would saturate the network almost immediately, even on their largest server class. Sorry Rackspace.

In comparison, Amazon's EC2 Cloud offers High Performance Computing nodes with 10 Gigabit interconnects: Amazon HPC

1 comment:

my-inner-voice said...

Corey, read the blog


“The biggest bottleneck for high performance computing is disk performance .... Adding 10Gbps networking will help, but will not solve the constraint of having remote SAN storage from the computing. Infiniband is much lower latency than 10 Gbps networking if this really is your bottleneck “