Loading...

OSDP for NetApp 7-Mode Destination Filers

Deprecated:

The OSDP feature is deprecated from the Commvault software in V11 SP15.

See End-of-Life, Deprecated and Extended Support - Features for information about deprecated features.

Open Systems Data Protection (OSDP) is a full-volume block-level incremental replication feature. It replicates heterogeneous data from UNIX and Windows partitions and volumes to NetApp 7-Mode destination filer. The replicated volume is a single LUN, with a single partition, on a Snapvault copy.

Technical Details of the OSDP Feature

The source volumes can be part of disks that are local or that are attached to the client. Or the source volumes can be from disks that are externally attached to the client from non-NetApp hardware arrays. OSDP uses OnCommand Unified Manager (OCUM) to provision the destination volumes to which data is replicated. On Windows volumes, data is replicated as a GUID Partition Table (GPT) LUN. On UNIX volumes, the replicated LUN has the same format as the source LUN.

The following figure shows the process that is involved in an OSDP backup:

How Open Systems Data Protection works

The Open Systems Data Protection replication happens in the context of IntelliSnap backup. To carry out the replication transfer, run or schedule the replication workflow from the storage policy to which all the clients that need to be protected are associated. The workflow, in turn, starts off individual IntelliSnap backup jobs for each of the associated subclients. Each IntelliSnap backup job for a subclient does the following:

  • Creates a software snapshot of the source data using the native snap engine such as VSS or QSnap/LVM.
  • Adds the volume to the OCUM dataset that corresponds to the primary snap copy of the storage policy to which the subclient is associated.
  • OCUM carries out provisioning tasks and requests from the destination filer to connect back to the client IntelliSnap for Open SystemsTransfer/IntelliSnap for Open SystemsTest process.
  • If the volume has never been protected before, then the OSDP agent performs a baseline transfer, i.e., transfers all blocks for the volume to the destination filer.
  • If the volume has been protected before, then the OSDP agent calculates all blocks that have changed for the volume since the last backup, using the SHA-1 checksum mechanism and a checksum database to transfer only the changed blocks to the destination file server. For a given volume, all backups, except the first, are incremental.

When the Open Systems Data Protection transfer to all the associated subclients is complete, a destination snapshot is taken on the destination vault copy and this snap is registered as the primary copy of data for that application against the primary snap copy. The software snap that was created at the start of the IntelliSnap backup job is deleted once the Open Systems Data Protection transfer for source snapshot is successful.

The following illustration depicts the modules:

Link-1: the backup processes interact with OCUMServer to add host and volumes to the OCUM dataset and to run backup.

Link-2: OCUMserver communicates to NDMPListener to get and validate host details.

Link-3: OCUMserver creates and updates the relationship between the secondary filer and instruct filer to get the data from LREPListener to protect the dataset.

Link-4: When Secondary Filer gets a backup request, it connects to the source host on port 10566 to get the replication data from the LREPListener.

The IntelliSnap job type maybe full, differential, or incremental, but the OSDP transfer is always incremental, once a baseline for a volume is established.

Processes Specific to Open Systems Data Protection

Replication workflow – Coordinates the backup processes for all subclients of the replication workflow.

NDMPListener – Listens on port 10000. The NDMPListener is required by the OCUM server for host validation, and file system directory hierarchy discovery and validation. This thread runs on the source host in the context of CVD in a thread and will start with CVD startup.

LREPListener – Listens on port 10566. It runs on the source host starts on-demand when the OSDP backup runs. This is the port through which data gets transferred to the destination filer. LREPListener continues to run even after the backup completes.

LREPCoordinator – Runs on the MediaAgent, associated with the storage policy on which the workflow is triggered. It is responsible for starting the on-demand OCUM job, which, in turn, triggers incremental updates from the source hosts to the destination filer for each of the source volumes involved in the OSDP backup job.

Mapping entities between IntelliSnap and OnCommand Unified Manager

IntelliSnap

OnCommand Unified Manager Entity

Storage policy snap copy and subclients associated with the snap copy

Dataset

Complete Source volume derived from subclient content

Dataset member

Storage policy snap copy

Storage Service

Last modified: 10/4/2019 7:58:24 PM