User guide

Restoring a Cluster from a Snapshot
A snapshot contains data from any databases that are running on your cluster, and also information about
your cluster, including the number of nodes, node type, and master user name. If you need to restore
your cluster from a snapshot, Amazon Redshift uses the cluster information to create a new cluster and
then restores all the databases from the snapshot data. The new cluster that Amazon Redshift creates
from the snapshot will have same configuration, including the number and type of nodes, as the original
cluster from which the snapshot was taken. The cluster is restored in the same region and Availability
Zone unless you specify another Availability Zone in your request.
You can monitor the progress of a restore by either calling the DescribeClusters API action, or viewing
the cluster details in the AWS Management Console. For an in-progress restore, these display information
such as the size of the snapshot data, the transfer rate, the elapsed time, and the estimated time remaining.
For a description of these metrics, go to RestoreStatus.
You cannot use a snapshot to revert an active cluster to a previous state.
Note
When you restore a snapshot into a new cluster, the default security group and parameter group
are used unless you specify different values.
Sharing Snapshots
You can share an existing manual snapshot with the users in as many as 20 AWS customer accounts
by authorizing access to the snapshot. A person logged in as a user in one of the authorized accounts
can then describe the snapshot or restore it to create a new Redshift cluster under their account. For
example, if you use separate AWS customer accounts for production and test, a user can log on using
the production account and share a snapshot with users in the test account. Someone logged on as a
test account user can then restore the snapshot to create a new cluster that is owned by the test account
for testing or diagnostic work.
A manual snapshot is permanently owned by the AWS customer account under which it was created.
Only users in the account owning the snapshot can authorize other accounts to access the snapshot, or
to revoke authorizations. Users in the authorized accounts can only describe or restore any snapshot
that has been shared with them; they cannot copy or delete snapshots that have been shared with them.
An authorization remains in effect until the snapshot owner revokes it. If an authorization is revoked, the
previously authorized user loses visibility of the snapshot and cannot launch any new actions referencing
the snapshot. If the account is in the process of restoring the snapshot when access is revoked, the
restore runs to completion.You cannot delete a snapshot while it has active authorizations; you must
first revoke all of the authorizations.
AWS customer accounts are always authorized to access snapshots owned by the account. Attempts to
authorize or revoke access to the owner account will receive an error.You cannot restore or describe a
snapshot that is owned by an inactive AWS customer account.
After you have authorized access to an AWS customer account, no IAM users in that account can perform
any actions on the snapshot unless they have IAM policies that allow them to do so.
• IAM users in the snapshot owner account can authorize and revoke access to a snapshot only if they
have an IAM policy that allows them to perform those actions with a resource specification that includes
the snapshot. For example, the following policy allows a user in AWS account 012345678912 to
authorize other accounts to access a snapshot named my-snapshot20130829:
{
"Version": "2012-10-17",
"Statement":[
{
API Version 2012-12-01
84
Amazon Redshift Management Guide
Restoring a Cluster from a Snapshot