Amazon Redshift clusters - Amazon Redshift

Amazon Redshift clusters

In the following sections, you can learn the basics of creating a data warehouse by launching a set of compute nodes, called an Amazon Redshift cluster.

Overview of Amazon Redshift clusters

An Amazon Redshift data warehouse is a collection of computing resources called nodes, which are organized into a group called a cluster. Each cluster runs an Amazon Redshift engine and contains one or more databases.

Note

At this time, Amazon Redshift version 1.0 engine is available. However, as the engine is updated, multiple Amazon Redshift engine versions might be available for selection.

Clusters and nodes in Amazon Redshift

An Amazon Redshift cluster consists of nodes. Each cluster has a leader node and one or more compute nodes. The leader node receives queries from client applications, parses the queries, and develops query execution plans. The leader node then coordinates the parallel execution of these plans with the compute nodes and aggregates the intermediate results from these nodes. It then finally returns the results back to the client applications.

Compute nodes execute the query execution plans and transmit data among themselves to serve these queries. The intermediate results are sent to the leader node for aggregation before being sent back to the client applications. For more information about leader nodes and compute nodes, see Data warehouse system architecture in the Amazon Redshift Database Developer Guide.

When you create a cluster on the Amazon Redshift console (https://console.aws.amazon.com/redshift/), you can get a recommendation of your cluster configuration based on the size of your data and query characteristics. To use this sizing calculator, look for Help me choose on the console in AWS Regions which support RA3 node types. For more information, see Creating a cluster.

When you launch a cluster, one option you specify is the node type. The node type determines the CPU, RAM, storage capacity, and storage drive type for each node.

Amazon Redshift offers different node types to accommodate your workloads, and we recommend choosing RA3 or DC2 depending on the required performance, data size, and expected data growth.

RA3 nodes with managed storage enable you to optimize your data warehouse by scaling and paying for compute and managed storage independently. With RA3, you choose the number of nodes based on your performance requirements and only pay for the managed storage that you use. Size your RA3 cluster based on the amount of data you process daily. You launch clusters that use the RA3 node types in a virtual private cloud (VPC). You can't launch RA3 clusters in EC2-Classic. For more information, see Creating a cluster in a VPC.

Amazon Redshift managed storage uses large, high-performance SSDs in each RA3 node for fast local storage and Amazon S3 for longer-term durable storage. If the data in a node grows beyond the size of the large local SSDs, Amazon Redshift managed storage automatically offloads that data to Amazon S3. You pay the same low rate for Amazon Redshift managed storage regardless of whether the data sits in high-performance SSDs or Amazon S3. For workloads that require ever-growing storage, managed storage lets you automatically scale your data warehouse storage capacity without adding and paying for additional nodes.

DC2 nodes enable you to have compute-intensive data warehouses with local SSD storage included. You choose the number of nodes you need based on data size and performance requirements. DC2 nodes store your data locally for high performance, and as the data size grows, you can add more compute nodes to increase the storage capacity of the cluster. For datasets under 1 TB (compressed), we recommend DC2 node types for the best performance at the lowest price. If you expect your data to grow, we recommend using RA3 nodes so you can size compute and storage independently to achieve improved price and performance. You launch clusters that use the DC2 node types in a virtual private cloud (VPC). You can't launch DC2 clusters in EC2-Classic. For more information, see Creating a cluster in a VPC.

DS2 nodes enable you to create large data warehouses using hard disk drives (HDDs), and we recommend using RA3 nodes instead. If you are using DS2 nodes, see Upgrading to RA3 node types for upgrade guidelines. If you are using eight or more nodes of ds2.xlarge, or any number of ds2.8xlarge nodes, you can now upgrade to RA3 to get 2x more storage and improved performance for the same on-demand cost.

Node types are available in different sizes. Node size and the number of nodes determine the total storage for a cluster. For more information, see Node type details.

Some node types allow one node (single-node) or two or more nodes (multi-node). The minimum number of nodes for clusters of some node types is two nodes. On a single-node cluster, the node is shared for leader and compute functionality. Single-node clusters are not recommended for running production workloads. On a multi-node cluster, the leader node is separate from the compute nodes. The leader node is the same node type as the compute nodes. You only pay for compute nodes.

Amazon Redshift applies quotas to resources for each AWS account in each AWS Region. A quota restricts the number of resources that your account can create for a given resource type, such as nodes or snapshots, within an AWS Region. For more information about the default quotas that apply to Amazon Redshift resources, see Amazon Redshift Limits in the Amazon Web Services General Reference. To request an increase, submit an Amazon Redshift Limit Increase Form.

The cost of your cluster depends on the AWS Region, node type, number of nodes, and whether the nodes are reserved in advance. For more information about the cost of nodes, see the Amazon Redshift pricing page.

Node type details

The following tables summarize the node specifications for each node type and size. The headings in the tables have these meanings:

  • vCPU is the number of virtual CPUs for each node.

  • RAM is the amount of memory in gibibytes (GiB) for each node.

  • Default slices per node is the number of slices into which a compute node is partitioned when a cluster is created or resized with classic resize.

    The number of slices per node might change if the cluster is resized using elastic resize. However the total number of slices on all the compute nodes in the cluster remains the same after elastic resize.

    When you create a cluster with the restore from snapshot operation, the number of slices of the resulting cluster might change from the original cluster if you change the node type.

  • Storage is the capacity and type of storage for each node.

  • Node Range is the minimum and maximum number of nodes that Amazon Redshift supports for the node type and size.

    Note

    You might be restricted to fewer nodes depending on the quota that is applied to your AWS account in the selected AWS Region. To request an increase, submit an Amazon Redshift Limit Increase Form.

  • Total Capacity is the total storage capacity for the cluster if you deploy the maximum number of nodes that is specified in the node range.

RA3 node types
Node size vCPU RAM (GiB) Default slices per node Managed storage quota per node Node range with create cluster Total capacity
ra3.4xlarge 12 96 4 64 TB1 2–322 4096 TB2,3
ra3.16xlarge 48 384 16 64 TB1 2–128 8192 TB3

1 Indicates the storage quota of Amazon Redshift managed storage.

2 An ra3.4xlarge node type can be created with 32 nodes but resized with elastic resize to a maximum of 64 nodes.

3 Total Managed Storage Quota is the maximum number of nodes times 64 TB.

Dense storage node types
Node size vCPU RAM (GiB) Default slices per node Storage per node Node range Total capacity
ds2.xlarge 4 31 2 2 TB HDD 1–32 64 TB
ds2.8xlarge 36 244 16 16 TB HDD 2–128 2 PB
Dense compute node types
Node size vCPU RAM (GiB) Default slices per node Storage per node Node range Total capacity
dc2.large 2 15 2 160 GB NVMe-SSD 1–32 5.12 TB
dc2.8xlarge 32 244 16 2.56 TB NVMe-SSD 2–128 326 TB
dc1.large1 2 15 2 160 GB SSD 1–32 5.12 TB
dc1.8xlarge1 32 244 32 2.56 TB SSD 2–128 326 TB

1 We recommend DC2 node types over DC1 node types. For more information on how to upgrade, see Upgrading from DC1 node types to DC2 node types.

Previous node type names

In previous releases of Amazon Redshift, certain node types had different names. You can use the previous names in the Amazon Redshift API and AWS CLI. However, we recommend that you update any scripts that reference those names to use the current names instead. The current and previous names are as follows.

Current name Previous names
ds2.xlarge ds1.xlarge, dw.hs1.xlarge, dw1.xlarge
ds2.8xlarge ds1.8xlarge, dw.hs1.8xlarge, dw1.8xlarge
dc1.large dw2.large
dc1.8xlarge dw2.8xlarge

Determining the number of nodes

Because Amazon Redshift distributes and executes queries in parallel across all of a cluster’s compute nodes, you can increase query performance by adding nodes to your cluster. When you run a cluster with at least two compute nodes, data on each node is mirrored on disks of another node to reduce the risk of incurring data loss.

You can monitor query performance in the Amazon Redshift console and with Amazon CloudWatch metrics. You can also add or remove nodes as needed to achieve the balance between price and performance for your cluster. When you request an additional node, Amazon Redshift takes care of all the details of deployment, load balancing, and data maintenance. For more information about cluster performance, see Monitoring Amazon Redshift cluster performance.

Reserved nodes are appropriate for steady-state production workloads, and offer significant discounts over on-demand nodes. You can purchase reserved nodes after running experiments and proof-of-concepts to validate your production configuration. For more information, see Purchasing Amazon Redshift reserved nodes.

When you pause a cluster, you suspend on-demand billing during the time the cluster is paused. During this paused time, you only pay for backup storage. This frees you from planning and purchasing data warehouse capacity ahead of your needs, and enables you to cost-effectively manage environments for development or test purposes.

For information about pricing of on-demand and reserved nodes, see Amazon Redshift pricing.

Use EC2-VPC when you create your cluster

Amazon Redshift clusters run in Amazon EC2 instances that are configured for the Amazon Redshift node type and size that you select. Create your cluster using EC2-VPC. If you are still using EC2-Classic, we recommend you use EC2-VPC to get improved performance and security. For more information about these networking platforms, see Supported Platforms in the Amazon EC2 User Guide for Linux Instances. Your AWS account settings determine whether EC2-VPC or EC2-Classic are available to you.

Note

To prevent connection issues between SQL client tools and the Amazon Redshift database, we recommend doing one of two things. You can configure an inbound rule that enables the hosts to negotiate packet size. Alternatively, you can disable TCP/IP jumbo frames by setting the maximum transmission unit (MTU) to 1500 on the network interface (NIC) of your Amazon EC2 instances. For more information about these approaches, see Queries appear to hang and sometimes fail to reach the cluster.

EC2-VPC

When using EC2-VPC, your cluster runs in a virtual private cloud (VPC) that is logically isolated to your AWS account. If you provision your cluster in the EC2-VPC, you control access to your cluster by associating one or more VPC security groups with the cluster. For more information, see Security Groups for Your VPC in the Amazon VPC User Guide.

To create a cluster in a VPC, you must first create an Amazon Redshift cluster subnet group by providing subnet information of your VPC, and then provide the subnet group when launching the cluster. For more information, see Amazon Redshift cluster subnet groups.

For more information about Amazon Virtual Private Cloud (Amazon VPC), see the Amazon VPC product detail page.

EC2-Classic

In EC2-Classic, your cluster runs in a single, flat network that you share with other AWS customers. If you provision your cluster in the EC2-Classic, you control access to your cluster by associating one or more Amazon Redshift cluster security groups with the cluster. For more information, see Amazon Redshift cluster security groups.

Launch a cluster

Your AWS account can either launch instances of both EC2-VPC and EC2-Classic, or only EC2-VPC, on a region-by-region basis. To determine which networking platform your account supports, and then launch a cluster, do the following:

  1. Decide which AWS Region you want to deploy a cluster. For a list of AWS Regions in which Amazon Redshift is available, see Amazon Redshift endpoints in the Amazon Web Services General Reference.

  2. Find out which Amazon EC2 platforms your account supports in the chosen AWS Region. You can find this information in the Amazon EC2 console. For step-by-step instructions, see Supported Platforms in the Amazon EC2 User Guide for Linux Instances.

  3. If your account supports both of the platforms, we recommend EC2-VPC. If your account supports only EC2-VPC, you must deploy your cluster in VPC.

  4. Launch your Amazon Redshift cluster. You can create a cluster using the Amazon Redshift console, or by using the Amazon Redshift API, AWS CLI, or SDK libraries. For more information about these options and links to the related documentation, see What is Amazon Redshift?.

Overview of RA3 node types

We recommend that you upgrade existing workloads running on DS2 node type clusters to RA3 node types to take advantage of improved performance and to get more storage capacity. RA3 nodes provide the following advantages:

  • They are flexible to grow your compute capacity without increasing your storage costs. And they scale your storage without over-provisioning compute capacity.

  • They use high performance SSDs for your hot data and Amazon S3 for cold data. Thus they provide ease of use, cost-effective storage, and high query performance.

  • They use high bandwidth networking built on the AWS Nitro System to further reduce the time taken for data to be offloaded to and retrieved from Amazon S3.

Consider choosing RA3 node types in these cases:

  • You need the flexibility to scale and pay for compute separate from storage.

  • You query a fraction of your total data.

  • Your data volume is growing rapidly or is expected to grow rapidly.

  • You want the flexibility to size the cluster based only on your performance needs.

To use RA3 node types, your AWS Region must support RA3. For more information, see RA3 node type availability in AWS Regions.

Important

You can use ra3.4xlarge node types only with cluster version 1.0.14104 or later. You can view the version of an existing cluster with the Amazon Redshift console. For more information, see Determining the cluster maintenance version.

Make sure that you use the new Amazon Redshift console when working with RA3 node types. The original console doesn't support all RA3 operations.

In addition, to use RA3 node types with Amazon Redshift operations that use the maintenance track, the maintenance track value must be set to a cluster version that supports RA3. For more information about maintenance tracks, see Choosing cluster maintenance tracks.

Working with Amazon Redshift managed storage

With Amazon Redshift managed storage, you can store and process all your data in Amazon Redshift while getting more flexibility to scale compute and storage capacity separately. You continue to ingest data with the COPY or INSERT command. To optimize performance and manage automatic data placement across tiers of storage, Amazon Redshift takes advantage of optimizations such as data block temperature, data block age, and workload patterns. When needed, Amazon Redshift scales storage automatically to Amazon S3 without requiring any manual action.

For information about storage costs, see Amazon Redshift pricing.

Managing RA3 node types

To take advantage of separating compute from storage, you can create or upgrade your cluster with the RA3 node type. To use the RA3 node types, create your clusters in a virtual private cloud (EC2-VPC).

To change the number of nodes of Amazon Redshift cluster with an RA3 node type, do one of the following:

  • Add or remove nodes with the elastic resize operation. In some situations, removing nodes from a RA3 cluster isn't allowed with elastic resize. For example, when a 2:1 node count upgrade puts the number of slices per node at 32. For more information, see Resizing clusters. If elastic resize isn't available, use classic resize.

  • Add or remove nodes with the classic resize operation. Choose this option when you are resizing to a configuration that isn't available through elastic resize. Elastic resize is quicker than classic resize. For more information, see Resizing clusters.

RA3 node type availability in AWS Regions

The RA3 node types are available only in the following AWS Regions:

  • US East (N. Virginia) Region (us-east-1)

  • US East (Ohio) Region (us-east-2)

  • US West (N. California) Region (us-west-1)

  • US West (Oregon) Region (us-west-2)

  • Asia Pacific (Mumbai) Region (ap-south-1)

  • Asia Pacific (Seoul) Region (ap-northeast-2)

  • Asia Pacific (Singapore) Region (ap-southeast-1)

  • Asia Pacific (Sydney) Region (ap-southeast-2)

  • Asia Pacific (Tokyo) Region (ap-northeast-1)

  • Canada (Central) Region (ca-central-1)

  • Europe (Frankfurt) Region (eu-central-1)

  • Europe (Ireland) Region (eu-west-1)

  • Europe (London) Region (eu-west-2)

  • Europe (Paris) Region (eu-west-3)

  • Europe (Stockholm) Region (eu-north-1)

  • South America (São Paulo) Region (sa-east-1)

Upgrading to RA3 node types

To upgrade your existing node type to RA3, you have the following options to change the node type:

  • Restore from a snapshot – Amazon Redshift uses the most recent snapshot of your DS2 or DC2 cluster and restores it to create a new RA3 cluster. As soon as the cluster creation is complete (usually within minutes), RA3 nodes are ready to run your full production workload. As compute is separate from storage, hot data is brought in to the local cache at fast speeds thanks to a large networking bandwidth. If you restore from the latest DS2 or DC2 snapshot, RA3 preserves hot block information of the DS2 or DC2 workload and populates its local cache with the hottest blocks. For more information, see Restoring a cluster from a snapshot.

    To keep the same endpoint for your applications and users, you can rename the new RA3 cluster with the same name as the original DS2 or DC2 cluster. To rename the cluster, modify the cluster in the Amazon Redshift console or ModifyCluster API operation. For more information, see Renaming clusters or ModifyCluster API operation in the Amazon Redshift API Reference.

  • Elastic resize – resize the cluster using elastic resize. When you use elastic resize to change node type, Amazon Redshift automatically creates a snapshot, creates a new cluster, deletes the old cluster, and renames the new cluster. The elastic resize operation can be run on-demand or can be scheduled to run at a future time. You can quickly upgrade your existing DS2 or DC2 node type clusters to RA3 with elastic resize. For more information, see Elastic resize.

The following table shows recommendations when upgrading to RA3 node types.

Existing node type Range of existing number of nodes Recommended new node type Upgrade action

ds2.xlarge

1–7

none

Keep existing ds2.xlarge cluster or upgrade to a dc2.large cluster. If you do not have enough data to fill the local disk, upgrading to a dc2.large can improve performance and reduce cost.

ds2.xlarge

8–128

ra3.4xlarge

Create 1 node of ra3.4xlarge for every 4 nodes of ds2.xlarge.

ds2.8xlarge

2–15

ra3.4xlarge

Create 2 nodes of ra3.4xlarge for every 1 node of ds2.8xlarge.

ds2.8xlarge

16–128

ra3.16xlarge

Create 1 node of ra3.16xlarge for every 2 nodes of ds2.8xlarge.

dc2.8xlarge

2–15

ra3.4xlarge

Create 2 nodes of ra3.4xlarge for every 1 node of dc2.8xlarge1.

dc2.8xlarge

16–128

ra3.16xlarge

Create 1 node of ra3.16xlarge for every 2 nodes of dc2.8xlarge1.

dc2.large

1–15

none

Keep existing dc2.large cluster.

dc2.large

16–128

ra3.4xlarge

Create 1 node of ra3.4xlarge for every 8 nodes of dc2.large1.

1Extra nodes might be needed depending on workload requirements. Add or remove nodes based on the compute requirements of your required query performance.

The minimum number of nodes for RA3 clusters is 2 nodes. Take this into consideration when creating an RA3 cluster.

If you have already purchased DS2 reserved nodes, contact AWS for help with converting DS2 reserved nodes to RA3 reserved nodes. To contact AWS for more information, see Amazon Redshift RA3 instances with managed storage.

Upgrading from DC1 node types to DC2 node types

To take advantage of performance improvements, you can upgrade your DC1 clusters to DC2 node types.

Clusters that use the DC2 node type must be launched in a virtual private cloud (EC2-VPC).

If your DC1 cluster is not in a VPC:

  1. Create a snapshot of your DC1 cluster. For more information, see Amazon Redshift snapshots.

  2. Create a VPC, then create a DC2 cluster in the VPC. For more information, see Managing clusters in a VPC.

  3. Restore your snapshot to the new DC2 cluster in the VPC. For more information, see Restoring a cluster from a snapshot.

If your DC1 cluster is already in a VPC, choose one of the following methods:

  • Resize your DC1 cluster and change the node type to DC2 as part of the operation. Your cluster is not available for a period of time during the resize operation. For more information, see Resizing clusters in Amazon Redshift.

  • Create a snapshot of your DC1 cluster, then restore your snapshot to a DC2 cluster in the VPC. For more information, see Restoring a cluster from a snapshot.

Consider the following when upgrading from DC1 to DC2 node types.

  • DC1 clusters that are 100% full might not upgrade to an equivalent number of DC2 nodes. If more disk space is needed, you can:

    • Resize to a configuration with more available disk space.

    • Clean up unneeded data by truncating tables or deleting rows.

  • DC2 clusters don't support EC2-Classic networking. If your DC1 cluster is not running in a VPC, create one for your DC2 migration. For more information, see Managing clusters in a VPC.

  • If you resize the cluster, it might be put into read-only mode for the duration of the operation. For more information, see Resizing clusters in Amazon Redshift.

  • If you have purchased DC1 reserved nodes, you can upgrade your DC1 reserved nodes to DC2 nodes for the remainder of your term. For more information about how to change your reservation with the AWS CLI, see Upgrading reserved nodes with the AWS CLI.

  • If you use restore to upgrade from dc1.large to dc2.large, and change the number of nodes, then the snapshot must have been created at cluster version 1.0.10013 or later.

  • If you use restore to upgrade from dc1.8xlarge to dc2.8xlarge, then the snapshot must have been created at cluster version 1.0.10013 or later.

  • If you use elastic resize to upgrade from DC1 to DC2, and change the number of nodes, then the cluster must be at cluster version 1.0.10013 or later.

  • If a snapshot of dc1.8xlarge cluster to upgrade is from a cluster earlier than version 1.0.10013, then first restore the snapshot from the dc1.8xlarge cluster into a new dc1.8xlarge cluster with the same number of nodes. Then use one of the following methods to upgrade the new dc1.8xlarge:

    • Use a snapshot from the new restored cluster to upgrade to dc2.8xlarge.

    • Use elastic resize to upgrade the new restored cluster to dc2.8xlarge.

Upgrading a DS2 cluster on EC2-Classic to EC2-VPC

Amazon Redshift clusters run in Amazon EC2 instances that are configured for the Amazon Redshift node type and size that you choose. We recommend that you upgrade your cluster on EC2-Classic to launch in a VPC using EC2-VPC for improved performance and security.

To upgrade your DS2 cluster on EC2-Classic to EC2-VPC

  1. Create a snapshot of your DS2 cluster. For more information, see Amazon Redshift snapshots.

  2. Create a VPC, then create a DS2 cluster in the VPC. For more information, see Managing clusters in a VPC.

  3. Restore your snapshot to the new DS2 cluster in the VPC. For more information, see Restoring a cluster from a snapshot.

Region and Availability Zone considerations

Amazon Redshift is available in several AWS Regions. By default, Amazon Redshift provisions your cluster in a randomly selected Availability Zone (AZ) within the AWS Region that you choose. All the cluster nodes are provisioned in the same Availability Zone.

You can optionally request a specific Availability Zone if Amazon Redshift is available in that zone. For example, if you already have an Amazon EC2 instance running in one Availability Zone, you might want to create your Amazon Redshift cluster in the same zone to reduce latency. On the other hand, you might want to choose another Availability Zone for higher availability. Amazon Redshift might not be available in all Availability Zones within an AWS Region.

For a list of supported AWS Regions where you can provision an Amazon Redshift cluster, see Amazon Redshift endpoints in the Amazon Web Services General Reference.

Cluster maintenance

Amazon Redshift periodically performs maintenance to apply upgrades to your cluster. During these updates, your Amazon Redshift cluster isn't available for normal operations. You have several ways to control how we maintain your cluster. For example, you can control when we deploy updates to your clusters. You can also choose whether your cluster runs the most recently released version, or the version released previously to the most recently released version. Finally, you have the option to defer non-mandatory maintenance updates for a period of time.

Maintenance windows

Amazon Redshift assigns a 30-minute maintenance window at random from an 8-hour block of time per AWS Region, occurring on a random day of the week (Monday through Sunday, inclusive).

Default maintenance windows

The following list shows the time blocks for each AWS Region from which the default maintenance windows are assigned:

  • US East (N. Virginia) Region: 03:00–11:00 UTC

  • US East (Ohio) Region: 03:00–11:00 UTC

  • US West (N. California) Region: 06:00–14:00 UTC

  • US West (Oregon) Region: 06:00–14:00 UTC

  • Africa (Cape Town) Region: 20:00–04:00 UTC

  • Asia Pacific (Hong Kong) Region: 13:00–21:00 UTC

  • Asia Pacific (Mumbai) Region: 16:30–00:30 UTC

  • Asia Pacific (Osaka-Local) Region: 13:00–21:00 UTC

  • Asia Pacific (Seoul) Region: 13:00–21:00 UTC

  • Asia Pacific (Singapore) Region: 14:00–22:00 UTC

  • Asia Pacific (Sydney) Region: 12:00–20:00 UTC

  • Asia Pacific (Tokyo) Region: 13:00–21:00 UTC

  • Canada (Central) Region: 03:00–11:00 UTC

  • China (Beijing) Region: 13:00–21:00 UTC

  • China (Ningxia) Region: 13:00–21:00 UTC

  • Europe (Frankfurt) Region: 06:00–14:00 UTC

  • Europe (Ireland) Region: 22:00–06:00 UTC

  • Europe (London) Region: 22:00–06:00 UTC

  • Europe (Milan) Region: 21:00–05:00 UTC

  • Europe (Paris) Region: 23:00–07:00 UTC

  • Europe (Stockholm) Region: 23:00–07:00 UTC

  • Middle East (Bahrain) Region: 13:00–21:00 UTC

  • South America (São Paulo) Region: 19:00–03:00 UTC

If a maintenance event is scheduled for a given week, it starts during the assigned 30-minute maintenance window. While Amazon Redshift is performing maintenance, it terminates any queries or other operations that are in progress. Most maintenance completes during the 30-minute maintenance window, but some maintenance tasks might continue running after the window closes. If there are no maintenance tasks to perform during the scheduled maintenance window, your cluster continues to operate normally until the next scheduled maintenance window.

You can change the scheduled maintenance window by modifying the cluster, either programmatically or by using the Amazon Redshift console. The window must be at least 30 minutes and not longer than 24 hours. For more information, see Managing clusters using the console.

Deferring maintenance

If you need to reschedule your cluster’s maintenance window, you have the option to defer maintenance by up to 45 days. For example, if your cluster's maintenance window is set to Wednesday 8:30 – 9:00 UTC and you need to have access to your cluster at that time, you can defer the maintenance to a later time period. We will not perform any maintenance on your cluster when you have specified a deferment, unless we need to update hardware.

If we need to update hardware or make other mandatory updates during your period of deferment, we notify you and make the required changes. Your cluster isn't available during these updates.

If you defer your cluster's maintenance, the maintenance window following your period of deferment is mandatory. It can't be deferred.

Note

You can't defer maintenance after it has started.

For more information, see Modifying a cluster.

Choosing cluster maintenance tracks

When Amazon Redshift releases a new cluster version, your cluster is updated during its maintenance window. You can control whether your cluster is updated to the most recent approved release or to the previous release.

The maintenance track controls which cluster version is applied during a maintenance window. When Amazon Redshift releases a new cluster version, that version is assigned to the current track, and the previous version is assigned to the trailing track. To set the maintenance track for the cluster, specify one of the following values:

  • Current – Use the most current approved cluster version.

  • Trailing – Use the cluster version before the current version.

  • Preview – Use the cluster version that contains new features available for preview.

For example, suppose that your cluster is currently running version 1.0.2762 and the Amazon Redshift current version is 1.0.3072. If you set the maintenance track value to Current, your cluster is updated to version 1.0.3072 (the next approved release) during the next maintenance window. If you set the maintenance track value to Trailing, your cluster isn't updated until there is a new release after 1.0.3072.

Preview tracks

A Preview track might not always be available to choose. When you choose a Preview track, a track name must also be selected. Preview tracks and its related resources are temporary, have functional limitations, and might not contain all current Amazon Redshift features available in other tracks. When working with preview tracks:

  • Use the new Amazon Redshift console when working with preview tracks. For example, when you create a cluster to use with preview features.

  • You can't switch a cluster from one preview track to another.

  • You can't switch a cluster to a preview track from a current or trailing track.

  • You can't restore from a snapshot created from a different preview track.

  • You can only use the preview track when creating a new cluster, or when restoring from a snapshot.

  • You can't restore from a snapshot created from a different preview track, or with a cluster maintenance version later than the preview track cluster version. For example, when you restore a cluster to a preview track, you can only use a snapshot created from an earlier cluster maintenance version than that of the preview track.

Switching between maintenance tracks

Changing tracks for a cluster is generally a one-time decision. You should exercise caution in changing tracks. If you change the maintenance track from Trailing to Current, we will update the cluster to the Current track release version during the next maintenance window. However, if you change the cluster's maintenance track to Trailing we won't update your cluster until there is a new release after the Current track release version.

Maintenance tracks and restore

A snapshot inherits the source cluster's maintenance track. If you change the source cluster's maintenance track after you take a snapshot, the snapshot and the source cluster are on different tracks. When you restore from the snapshot, the new cluster will be on the maintenance track that was inherited from the source cluster. You can change the maintenance track after the restore operation completes. Resizing a cluster doesn't affect the cluster's maintenance track.

For more information see, Setting the maintenance track for a cluster.

Managing cluster versions

A maintenance track is a series of releases. You can decide if your cluster is on the Current track or the Trailing track. If you put your cluster on the Current track, it will always be upgraded to the most recent cluster release version during its maintenance window. If you put your cluster on the Trailing track, it will always run the cluster release version that was released immediately before the most recently released version.

The Release status column in the Amazon Redshift console list of clusters indicates whether one of your clusters is available for upgrade.

Rolling back the cluster version

If your cluster is up to date with the latest cluster version, you can choose to roll it back to the previous version.

For detailed information about features and improvements included with each cluster version, see Cluster version history.

Note

A new console is available for Amazon Redshift. Choose either the New console or the Original console instructions based on the console that you are using. The New console instructions are open by default.

To roll back to a previous cluster version

  1. Sign in to the AWS Management Console and open the Amazon Redshift console at https://console.aws.amazon.com/redshift/.

  2. On the navigation menu, choose CLUSTERS.

  3. Choose the cluster to roll back.

  4. For Actions, choose Roll back cluster version. The Roll back cluster version page appears.

  5. If there is a version available for roll back, follow the instructions on the page.

  6. Choose Roll back now.

To roll back to a previous cluster version

  1. Sign in to the AWS Management Console and open the Amazon Redshift console at https://console.aws.amazon.com/redshift/.

  2. In the navigation pane, choose Clusters.

  3. Choose the cluster that you want to roll back and choose the Status tab.

    If there is a version available to roll back to, it appears on the status tab of the details page.

    
                            Roll-back version details screen
  4. Choose Rollback to release (release number).

Determining the cluster maintenance version

You can determine the Amazon Redshift engine and database version with the Amazon Redshift console.

Note

A new console is available for Amazon Redshift. Choose either the New console or the Original console instructions based on the console that you are using. The New console instructions are open by default.

To find the version of a cluster

  1. Sign in to the AWS Management Console and open the Amazon Redshift console at https://console.aws.amazon.com/redshift/.

  2. On the navigation menu, choose CLUSTERS, then choose the cluster name from the list to open its details. The details of the cluster are displayed, including Cluster performance, Query monitoring, Maintenance and monitoring, Backup, Properties, and Schedules tabs.

  3. Choose the Maintenance and monitoring tab for more details.

  4. In the Maintenance section, find Current cluster version.

Note

Although the console displays this information in one field, it's two parameters in the Amazon Redshift API, ClusterVersion and ClusterRevisionNumber. For more information, see Cluster in the Amazon Redshift API Reference.

You can determine the Amazon Redshift engine and database versions for your cluster in the Cluster Version field in the console. The first two sections of the number are the cluster version, and the last section is the specific revision number of the database in the cluster. In the following example, the cluster version is 1.0 and the database revision number is 884.

Note

Although the console displays this information in one field, it’s two parameters in the Amazon Redshift API, ClusterVersion and ClusterRevisionNumber. For more information, see Cluster in the Amazon Redshift API Reference.

To specify whether to automatically upgrade the Amazon Redshift engine in your cluster if a new version of the engine becomes available, use the setting Allow version upgrade. This setting doesn't affect the database version upgrades, which are applied during the maintenance window that you specify for your cluster. Amazon Redshift engine upgrades are major version upgrades, and Amazon Redshift database upgrades are minor version upgrades. You can disable automatic version upgrades for major versions only. For more information about maintenance windows for minor version upgrades, see Maintenance windows.

Default disk space alarm

When you create an Amazon Redshift cluster, you can optionally configure an Amazon CloudWatch alarm to monitor the average percentage of disk space that is used across all of the nodes in your cluster. We’ll refer to this alarm as the default disk space alarm.

The purpose of default disk space alarm is to help you monitor the storage capacity of your cluster. You can configure this alarm based on the needs of your data warehouse. For example, you can use the warning as an indicator that you might need to resize your cluster. You might resize either to a different node type or to add nodes, or perhaps to purchase reserved nodes for future expansion.

The default disk space alarm triggers when disk usage reaches or exceeds a specified percentage for a certain number of times and at a specified duration. By default, this alarm triggers when the percentage that you specify is reached, and stays at or above that percentage for five minutes or longer. You can edit the default values after you launch the cluster.

When the CloudWatch alarm triggers, Amazon Simple Notification Service (Amazon SNS) sends a notification to specified recipients to warn them that the percentage threshold is reached. Amazon SNS uses a topic to specify the recipients and message that are sent in a notification. You can use an existing Amazon SNS topic; otherwise, a topic is created based on the settings that you specify when you launch the cluster. You can edit the topic for this alarm after you launch the cluster. For more information about creating Amazon SNS topics, see Getting Started with Amazon Simple Notification Service.

After you launch the cluster, you can view and edit the alarm from the cluster’s Status window under CloudWatch Alarms. The name is percentage-disk-space-used-default-<string>. You can open the alarm to view the Amazon SNS topic that it is associated with and edit alarm settings. If you did not select an existing Amazon SNS topic to use, the one created for you is named <clustername>-default-alarms (<recipient>); for example, examplecluster-default-alarms (notify@example.com).

For more information about configuring and editing the default disk space alarm, see Creating a cluster and Creating or editing a disk space alarm.

Note

If you delete your cluster, the alarm associated with the cluster will not be deleted but it will not trigger. You can delete the alarm from the CloudWatch console if you no longer need it.

Cluster status

The cluster status displays the current state of the cluster. The following table provides a description for each cluster status.

Status Description
available The cluster is running and available.
available, prep-for-resize The cluster is being prepared for elastic resize. The cluster is running and available for read and write queries, but cluster operations, such as creating a snapshot, are not available.
available, resize-cleanup An elastic resize operation is completing data transfer to the new cluster nodes. The cluster is running and available for read and write queries, but cluster operations, such as creating a snapshot, are not available.
cancelling-resize The resize operation is being cancelled.
creating Amazon Redshift is creating the cluster. For more information, see Creating a cluster.
deleting Amazon Redshift is deleting the cluster. For more information, see Deleting a cluster.
final-snapshot Amazon Redshift is taking a final snapshot of the cluster before deleting it. For more information, see Deleting a cluster.
hardware-failure

The cluster suffered a hardware failure.

If you have a single-node cluster, the node cannot be replaced. To recover your cluster, restore a snapshot. For more information, see Amazon Redshift snapshots.

incompatible-hsm Amazon Redshift cannot connect to the hardware security module (HSM). Check the HSM configuration between the cluster and HSM. For more information, see Encryption for Amazon Redshift using hardware security modules.
incompatible-network There is an issue with the underlying network configuration. Make sure that the VPC in which you launched the cluster exists and its settings are correct. For more information, see Managing clusters in a VPC.
incompatible-parameters There is an issue with one or more parameter values in the associated parameter group, and the parameter value or values cannot be applied. Modify the parameter group and update any invalid values. For more information, see Amazon Redshift parameter groups.
incompatible-restore There was an issue restoring the cluster from the snapshot. Try restoring the cluster again with a different snapshot. For more information, see Amazon Redshift snapshots.
modifying Amazon Redshift is applying changes to the cluster. For more information, see Modifying a cluster.
paused The cluster is paused. For more information, see Pausing and resuming clusters.
rebooting Amazon Redshift is rebooting the cluster. For more information, see Rebooting a cluster.
renaming Amazon Redshift is applying a new name to the cluster. For more information, see Renaming clusters.
resizing Amazon Redshift is resizing the cluster. For more information, see Resizing a cluster.
rotating-keys Amazon Redshift is rotating encryption keys for the cluster. For more information, see Encryption key rotation in Amazon Redshift.
storage-full The cluster has reached its storage capacity. Resize the cluster to add nodes or to choose a different node size. For more information, see Resizing a cluster.
updating-hsm Amazon Redshift is updating the HSM configuration. .