It is possible to use CloudWatch to monitor your disk and memory usage. There are very good information on AWS – http://docs.aws.amazon.com/AmazonCloudWatch/latest/DeveloperGuide/mon-scripts-perl.html
For the impatient, here is how to get it done.
First, install the required packages
% yum install perl-DateTime perl-Sys-Syslog perl-LWP-Protocol-https
% wget http://aws-cloudwatch.s3.amazonaws.com/downloads/CloudWatchMonitoringScripts-1.2.1.zip
Unzip the zip file into /usr/local/bin. Then create the following cronjob:
*/5 * * * * /usr/local/bin/mon-put-instance-data.pl --disk-path=/ --disk-space-util --from-cron --aws-access-key-id=xxx --aws-secret-key=xxx
That’s it, in a few minutes, you should start seeing the graphs under “Linux System Metrics”. Here is what it looks like
Of course, to use the cronjob, you need to grant at least CloudWatchFullAccess to a user and replace the “xxx” to the actual id and key.