Amazon EC2 and EBS using Windows AMIs

Question

I put our application on EC2 (Windows 2003 x64 server) and attached up to 7 EBS volumes. The app is very I/O intensive to storage -- typically we use DAS with NTFS mount points (usually around 32 mount points, each to 1TB drives) so i tried to replicate that using EBS but the I/O rates are bad as in 22MB/s tops. We suspect the NIC card to the EBS (which are dymanic SANs if i read correctly) is limiting the pipeline. Our app uses mostly streaming for disk access (not random) so for us it works better when very little gets in the way of our talking to the disk controllers and handling IO directly.

Also when I create a volume and attach it, I see it appear in the instance (fine) and then i make it into a dymamic disk pointing to my mount point, then quick format it -- when I do this does all the data on the volume get wiped? Because it certainly seems so when i attach it to another AMI. I must be missing something.

I'm curious if anyone has any experience putting IO intensive apps up on the EC2 cloud and if so what's the best way to setup the volumes?

Thanks!

Answer 1

I've had limited experience, but I have noticed one small thing:

The initial write is generally slower than subsequent writes.

So if you're streaming a lot of data to disk, like writing logs, this will likely bite you. But if you make a big file fill it with data, and do a lot of random access I/O to it, it gets better on the second time writing to any specific location.