1. Legato NetWorker – RMAN Integration
Michael Preetz
Advisory SE

2. Regular Backups
Regular backups are the standard backups NMO has always performed.
They are also referred to as non-proxy backups or conventional backups.
Regular backups are data stream based backups. Oracle reads the data from the Oracle data files and passes it to NMO in buffers. NMO then passes the data to nsrmmd to be written to storage media.
NMO does not interpret the data being backed up. It treats the data as opaque blocks.

3. Regular Manual Backup Diagram

4. Regular Restores Regular restores are restores of regular backups.
The data is passed from nsrmmd to NMO which then passes it to Oracle. Oracle then writes the data to the appropriate data file.
NMO does not interpret the data being restored. It treats the data as opaque block.

5. Regular Restore Diagram

6. Proxy Copy Backups
Proxy copy backups are backups where Oracle does not read the data from the disk.
Oracle passes a list of the files to be backed up to the MML. The MML then backs up the files using any method it desires.
Oracle implemented proxy copy so storage vendors could provide snapshot enabled MMLs.
Proxy copy backups are supported by Oracle and higher.

7. Simplified Proxy Copy Backup Workflow
The default workflow of a proxy copy backup is:
1. Oracle passes the MML a list of files to be backed up.
2. The MML tells Oracle which files can be backed up with proxy copy and which cannot.
3. Oracle places the files that can be backed up with proxy copy into hot backup mode.
4. The MML creates snapshots of the files.
5. Oracle takes the files out of hot backup mode.
6. The MML writes the files to secondary storage (i.e. tape) if required.

8. Proxy Copy Restores
Proxy copy restores are restores of proxy copy backups.
During proxy copy restores Oracle passes NMO a list of files to be restored. NMO then restores the files using any method it desires.
Proxy copy restores are supported by any version of Oracle that performs proxy copy backups.

9. Simplified Proxy Copy Restore Workflow
The default workflow of a proxy copy restore is:
1. Oracle passes the MML a list of files to be restored.
2. The MML tells Oracle which files can be restored with proxy copy and which cannot.
3. If all the files can be restored with proxy copy the MML restores the files.

10. PowerSnap Modules
The PowerSnap modules provide snapshot services to applications (i.e. NMO)
Applications request snapshot operations from PowerSnap modules by making BRC API calls to the nsrpsd through RPC.
The nsrpsd is the daemon that provides a common interface to all the PowerSnap modules on a system.

11. Architecture Diagram Snapshot Management CLI Application/LNM BRC API
Snapshot Policy management - Scheduling - Snapshot retention policy
Consistency check
Snapshot Management
CLI
Application/LNM
Application specifics for B&R
Translate Application object to physical/logical files
BRC API
PowerSnap-core
Implement workflows for performing IB, IR, Rollback, backup using snapshot
SC API
Snapshot Control
Snapshot provider nuances for creation, deletion, import and export of snapshots
Vendor APIs

12. Scheduled Instant Backup Diagram

13. The NMO Scheduled Instant Backup Diagram
From nsrsnap
nsrnmo
Oracle Process
RMAN
To nsrpsd
NMO Library
nsrnmostart
Legend
Spawned By
Interprocess
Communication
Process

14. Instant Restore Diagram

15. The NMO Instant Restore Diagram
Oracle Process
To nsrpsd
RMAN
NMO Library
Legend
Spawned By
Interprocess
Communication
Process

16. Catalog Synchronization
Catalog synchronization is performed during the PowerSnap consistency checking and when PowerSnap is releasing snapshot resources (i.e. beginning of a backup, re-labeling a tape)
When NMO savesets created by PowerSnap are being removed from the NetWorker indexes the nsrpsd spawns the nsroraclecat process.
The nsroraclecat process removes the proxy copy names from the RMAN repository that correspond to the NMO savesets.

17. Catalog Synchronization Diagram

18. Limitations of Catalog Synchronization
Only proxy copy backups can be synchronized.
Only one RMAN repository per Oracle SID is supported.
Nsroraclecat should never be run manually. If the DBA wants to synchronize the catalogs manually they should used the RMAN ‘crosscheck’ command.

19. Cluster and OPS Support

20. OPS/RAC and Cluster Support
For regular backups and restores, OPS/RAC and cluster support are identical to NMO 3.5.
OPS/RAC is not supported with proxy copy.
Clusters are supported with proxy copy.

21. Clusters
Proxy copy cluster backups are very similar to regular cluster backups. The differences are:
The NSR_CLIENT NMO parameter should not be
set.
The functionality of NSR_CLIENT can be emulated by setting the ‘-c’ option in the ‘backup command’ field of the NSR client resource.

22. Clusters (cont.)
For example, when backing up virtual machine foo the index entries can be redirected to bar by setting the ‘backup command’ in the NSR client resource to:
nsrnmo –c bar

23. Clusters (cont.)
The ‘-c’ option can be used to specify what machine a cluster backup runs on.
For example:
- A cluster has the virtual name ‘foo’.
- It is composed of two machines - ‘bar’ and ‘beque’.
- The DBA wants the backup to start on ‘bar’.
- The DBA wants the index entries to be written to ‘foo’.

24. Clusters (cont.) To accomplish this:
The DBA places the NSR client resource for ‘bar’ in the savegrp to be run.
The DBA places the following in the ‘backup command’ field of the NSR client resource of ‘bar’:
nsrnmo –c foo