Cassandra AWS Storage Requirements
Cassandra AWS Storage Requirements
Cassandra does a lot sequential disk IO for the commit log and writing out SSTable. You still need random I/O for read operations. The more read operations that are cache misses, the more your EBS volumes need IOPS.
Cassandra writes to four areas
- commit logs
- SSTable
- an index file
- a bloom filter
Consider EC2 instance store instead of EBS for Cassandra
AWS provides EC2 instance local storage called instance storage which is not available with all EC2 instance types, and Elastic Block Store (EBS). Instance storage does not have to go over a SAN or Intranet, instead it uses the local hardware bus. Instance storage is right there on the server you are renting. The downside of EC2 instance storage is the expense, and it is not as flexible as EBS. Due to historic problems with EBS, it used to be the only real option for running Cassandra in AWS. EBS has a reputation for degrading performance over time. Some of this has likely been fixed with enhanced EBS, but instance storage is more reliable.