IDedupReadFileCallback::PreviewContainerRead method (ddpbackup.h)

Article
02/22/2024

Provides the application with a preview of the sequence of reads that are pending for a given container file extent.

Syntax

HRESULT PreviewContainerRead(
  [in] BSTR            FileFullPath,
  [in] ULONG           NumberOfReads,
  [in] DDP_FILE_EXTENT *ReadOffsets
);

Parameters

[in] FileFullPath

The full path from the root directory of the volume to the container file.

[in] NumberOfReads

Number of DDP_FILE_EXTENT structures in the array that the ReadOffsets parameter points to.

[in] ReadOffsets

Pointer to an array of DDP_FILE_EXTENT structures.

Return value

This method can return standard HRESULT values, such as S_OK. It can also return converted system error codes using the HRESULT_FROM_WIN32 macro. Possible return values include the following.

Remarks

PreviewContainerRead is called for each container file extent reported by IDedupReadFileCallback::OrderContainersRestore. The application may use this preview as a per-container extent read plan to increase the efficiency of the pending reads. For example, the application may choose to perform read-ahead to improve throughput or to cache read buffers to improve overall performance across parallel file restore operations.

Requirements

Requirement	Value
Minimum supported client	None supported
Minimum supported server	Windows Server 2012
Target Platform	Windows
Header	ddpbackup.h