Q: What is a search instance?

A search instance is a single search engine in the cloud that indexes documents and responds to search requests. It has a finite amount of RAM and CPU resources for indexing data and processing requests.

Q: What is a search partition?

A search partition is the portion of your data which fits on a single search instance. A search domain can have one or more search partitions, and the number of search partitions can change as your documents are indexed.

Q: How does my search domain scale to meet my application needs?

Search domains scale in two dimensions: data and traffic. As your data volume grows, you need more (or larger) Search instances to contain your indexed data, and your index is partitioned among the search instances. As your request volume or request complexity increases, each Search Partition must be replicated to provide additional CPU for that Search Partition. For example, if your data requires three search partitions, you will have 3 search instances in your search domain. As your traffic increases beyond the capacity of a single search instance, each partition is replicated to provide additional CPU capacity, adding an additional three search instances to your search domain. Further increases in traffic will result in additional replicas, to a maximum of 5, for each search partition.

Q: How much data can I upload to my search domain?

The number of partitions you need depends on your data and configuration, so the maximum data you can upload is the data set that when your search configuration is applied results in 10 search partitions. When you exceed your search partition limit, your domain will stop accepting uploads until you delete documents and re-index your domain. If you need more than 10 search partitions, please contact us.

Q: Do I need to select the number and type of search instances for my search domain?

CloudSearch is a fully managed search service that automatically scales your search domain and selects the number and type of search instances. All search instances in a given search domain are of the same type and this type can change over time as your data or traffic grows.

You can also configure scaling options for an Amazon CloudSearch domain to:

Q: What instance types does Amazon CloudSearch support?

Amazon CloudSearch supports the following instance types:

Q: How do I find out the number and type of search instances in my search domain?

You can find out the number and type of search instances in your search domain by using the AWS Management Console, AWS SDKs, or AWS CLI. The number and type of search instances change over time and automatically scale up and down according to your indexable data and search traffic.

Q: How quickly does my search domain scale to accommodate changes in data and traffic?

Search domains typically react to increases in traffic changes within minutes. Changes in data volume or a reduction in traffic might take longer but you can accelerate this process by invoking an IndexDocuments operation. If you are about to upload a large amount of data or expect a surge in query traffic, you can prescale your domain by setting the desired instance type and replication count. For more information, see Configuring Scaling Options in the Amazon CloudSearch Developer Guide.

Q: Does Amazon CloudSearch support Multi-AZ deployments?

Yes. Amazon CloudSearch supports Multi-AZ deployments. When you enable the Multi-AZ option, Amazon CloudSearch provisions and maintains extra instances for your search domain in a second Availability Zone to ensure high availability. Updates are automatically applied to the instances in both Availability Zones. Search traffic is distributed across all of the instances and the instances in either zone are capable of handling the full load in the event of a failure.

Q: How does the new Multi-AZ feature work? Will my system experience any downtime in the event of a failure?

When the Multi-AZ option is enabled, Amazon CloudSearch instances in either zone are capable of handling the full load in the event of a failure. If there's service disruption or the instances in one zone become degraded, Amazon CloudSearch routes all traffic to the other Availability Zone. Redundant instances are restored in a separate Availability Zone without any administrative intervention or disruption in service.

Some inflight queries might fail and will need to be retried. Updates sent to the search domain are stored durably and will not be lost in the event of a failure.

Q: Can a search domain be deployed in more than 2 Availability Zones?

No. The maximum number of Availability Zones a domain can be deployed in is two.

Q: Can I modify the Multi-AZ configuration on my search domain?

Yes. You can turn the Multi-AZ configuration on and off for your search domains. The service is not interrupted when this setting is changed.

Q: Can I choose which Availability Zones my search domain is deployed in?

No. At this time Amazon CloudSearch automatically chooses an alternate Availability Zone in the same Region.

Q: Can I choose the instance type my domain uses?

Yes. With the latest release, Amazon CloudSearch enables you to specify the desired instance type for your domain. If necessary, Amazon CloudSearch will scale your domain up to a larger instance type, but will never scale back to a smaller instance type.

Q: What is the fastest way to get my data into CloudSearch?

By default, all domains start out on a small search instance. If you need to upload a large amount of data, you should prescale your domain to a larger instance type. For more information, see Bulk Uploads in the Amazon CloudSearch Developer Guide.

Q: How do I know which instance type I should choose for my initial setup?

For datasets of less than 1 GB of data or fewer than one million 1 KB documents, start with the default settings of a single small search instance. For larger data sets consider pre-warming the domain by setting the desired instance type. For data sets up to 8 GB, start with a large search instance. For datasets between 8 GB and 16 GB, start with an extra large search instance. For datasets between 16 GB and 32 GB, start with a double extra large search instance. Contact us if you need more upload capacity or have more than 500 GB to index.