Request Syntax URI Request Parameters Request Body Response Syntax Response Elements Errors See Also

ListChangedBlocks

Returns information about the blocks that are different between two Amazon EBS snapshots of the same volume or between two snapshot copies of the same source snapshot.

If you specify snapshot copies, the API returns the difference only if the two snapshots are incremental copies. For more information, see Incremental snapshot copying.

You must have permissions to access the specified snapshots.

Note

You should always retry requests that receive server (5xx) error responses, and ThrottlingException and RequestThrottledException client error responses. For more information see Error retries in the Amazon Elastic Compute Cloud User Guide.

Request Syntax


GET /snapshots/secondSnapshotId/changedblocks?firstSnapshotId=FirstSnapshotId&maxResults=MaxResults&pageToken=NextToken&startingBlockIndex=StartingBlockIndex HTTP/1.1

URI Request Parameters

The request uses the following URI parameters.

FirstSnapshotId

The ID of the first snapshot to use for the comparison.

Important

The FirstSnapshotID parameter must be specified with a SecondSnapshotId parameter; otherwise, an error occurs.

Length Constraints: Minimum length of 1. Maximum length of 64.

Pattern: ^snap-[0-9a-f]+$

MaxResults

The maximum number of blocks to be returned by the request.

Even if additional blocks can be retrieved from the snapshot, the request can return less blocks than MaxResults or an empty array of blocks.

To retrieve the next set of blocks from the snapshot, make another request with the returned NextToken value. The value of NextToken is null when there are no more blocks to return.

Valid Range: Minimum value of 100. Maximum value of 10000.

NextToken

The token to request the next page of results.

If you specify NextToken, then StartingBlockIndex is ignored.

Length Constraints: Maximum length of 256.

Pattern: ^[A-Za-z0-9+/=]+$

secondSnapshotId

The ID of the second snapshot to use for the comparison.

Important

The SecondSnapshotId parameter must be specified with a FirstSnapshotID parameter; otherwise, an error occurs.

Length Constraints: Minimum length of 1. Maximum length of 64.

Pattern: ^snap-[0-9a-f]+$

Required: Yes

StartingBlockIndex

The block index from which the comparison should start.

The list in the response will start from this block index or the next valid block index in the snapshots.

If you specify NextToken, then StartingBlockIndex is ignored.

Valid Range: Minimum value of 0.

Request Body

The request does not have a request body.

Response Syntax


HTTP/1.1 200
Content-type: application/json

{
   "BlockSize": number,
   "ChangedBlocks": [ 
      { 
         "BlockIndex": number,
         "FirstBlockToken": "string",
         "SecondBlockToken": "string"
      }
   ],
   "ExpiryTime": number,
   "NextToken": "string",
   "VolumeSize": number
}

Response Elements

If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.

BlockSize

The size of the blocks in the snapshot, in bytes.

Type: Integer

ChangedBlocks

An array of objects containing information about the changed blocks.

Type: Array of ChangedBlock objects

ExpiryTime

The time when the BlockToken expires.

Type: Timestamp

NextToken

The token to use to retrieve the next page of results. This value is null when there are no more results to return.

Type: String

Length Constraints: Maximum length of 256.

Pattern: ^[A-Za-z0-9+/=]+$

VolumeSize

The size of the volume in GB.

Type: Long

Valid Range: Minimum value of 1.

Errors

For information about the errors that are common to all actions, see Common Errors.

AccessDeniedException

You do not have sufficient access to perform this action.

HTTP Status Code: 403

InternalServerException

An internal error has occurred. For more information see Error retries.

HTTP Status Code: 500

RequestThrottledException

The number of API requests has exceeded the maximum allowed API request throttling limit for the snapshot. For more information see Error retries.

HTTP Status Code: 400

ResourceNotFoundException

The specified resource does not exist.

HTTP Status Code: 404

ServiceQuotaExceededException

Your current service quotas do not allow you to perform this action.

HTTP Status Code: 402

ValidationException

The input fails to satisfy the constraints of the EBS direct APIs.

HTTP Status Code: 400