Planning a DSE cluster on Amazon EC2
Information about deploying a production DataStax Enterprise cluster on Amazon EC2.
Before planning an Amazon Elastic Computer Cloud (Amazon EC2) cluster, read Amazon EC2 - Virtual Server Hosting.
- To ensure your implementation meets expectations, DataStax recommends contacting the DataStax Services team.
- Thoroughly test your configuration before deployment.
- Amazon periodically updates its offerings. Check the Amazon EC2 documentation to determine what instances to use.
Use AMIs from trusted sources
Use only AMIs for supported platforms and from a trusted source. Random AMIs pose a security risk and may perform slower than expected due to the way the EC2 install is configured. The following are examples of trusted AMIs:
EC2 deployments for multiple regions/availability zones
For these deployments use any of the supported platform on each node:
It is best practice to use the same platform on all nodes. If your cluster was instantiated using the DataStax AMI (no longer supported), use Ubuntu for the additional nodes. Configure the cluster as a multiple datacenter cluster using the Configuring Amazon EC2 multi-region snitch.
Guidelines for EC2 production clusters
- EBS General Purpose SSD (gp2) volumes
- To achieve IO required by DSE, you must use 3.5TB volumes, regardless of the actual space used, because gp2 provides 3 IOPS per GB.
- Amazon EBS Provisioned IOPS SSD (io1) volumes
- EBS io1 with 10,000 provisioned IOPS (PIOPS) provides the same performance level as gp2 using smaller volumes but at a higher cost.
- Directly attached local SSDs
- Also called ephemeral or instance SSDs. This storage type makes i3 instances the optimal cost versus performance choice. See pricing in Amazon AWS.
- Light production with only transactional nodes and very light-weight usage: m4.2xlarge (absolute minimum). Also suitable for development.
- Moderate production: i3.4xlarge
- Large production: i3.8xlarge
- DSE Search and DSE Analytic nodes: i3.4xlarge or i3.8xlarge
EBS volumes recommended for m4 instance types
GP2 | PIOPS |
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EBS magnetic volumes not recommended
EBS magnetic volumes are not recommended for DSE data storage volumes for the following reasons:
- EBS magnetic volumes contend directly for network throughput with standard packets. This contention means that EBS throughput is likely to fail when a network link is saturated.
- EBS magnetic volumes have unreliable performance. I/O performance can be exceptionally slow, causing the system to back load reads and writes until the entire cluster becomes unresponsive.
- Adding capacity by increasing the number of EBS volumes per host does not scale. You can easily surpass the ability of the system to keep effective buffer caches and concurrently serve requests for all of the data it is responsible for managing.
For more information and graphs related to ephemeral versus EBS performance, see Systematic Look at EC2 I/O.
Disk Performance Optimization
To ensure high disk performance to mounted drives, it is recommended that you pre-warm your drives by writing once to every drive location before production use. Depending on EC2 conditions, you can get moderate to enormous increases in throughput. See Optimizing Disk Performance in the Amazon Elastic Compute Cloud Documentation.
Storage recommendations
EC2 security group
When deploying a cluster on EC2, you must create security rules that open ports to other nodes in the same security group. An EC2 Security Group acts as a firewall that allows you to choose which protocols and ports are open in your cluster. You can specify the protocols and ports either by a range of IP addresses or by security group. For more information, see the Amazon EC2 help on Security Groups.
See the list of ports that should be opened to internode and client communications in the DataStax Enterprise ports table.