Views:

Details

General NDMP

1. What is NDMP?

NDMP is an acronym for Network Data Management Protocol and is an open standard protocol for enterprise-wide backup of heterogeneous network-attached storage.
The Network Data Management Protocol is defined in fine granularity within the NDMP specification. However, a quick synopsis follows:
Currently an NDMP server can be thought of providing two services:

A data server - This service either reads from disk and produces an NDMP data stream (in a specified format) or reads an NDMP data stream and writes to disk, depending upon whether a backup or restore is taking place.
A tape server - This service either reads an NDMP data stream and writes it to tape or reads from tape and writes an NDMP data stream, depending upon whether a backup or restore is taking place. All tape-handling functions, such as split-image issues, are dealt with by this service.

Each service has a separate state diagram that dictates its behavior. For example, the tape server (mover state machine) can enter the pause state while tapes are being changed by the NDMP client.
NDMP messages are categorized into distinct groups or NDMP interfaces, such as SCSI, CONFIG and TAPE. These messages as well as actions and errors can trigger state changes.
For additional information regarding NDMP, go to http://www.ndmp.org/info/faq.shtml.
Back

2. Which version of NDMP is required by DPX?

For full functionality including the Advanced Recovery and NetApp Open System SnapVault backups, DPX requires NDMP version 4 which is currently the latest.

Back

3. How do I determine the version of NDMP on the NetApp storage system?

To validate NDMP version:

a)    telnet to NetApp storage system
b)    type “ndmpd version” - will display currently set NDMP
c)    “ndmpd version 4” – will set to NDMP version 4
For more information about supported NDMP versions, see the DPX Operations Guide, DPX User’s Guide, or DPX Reference Guide on MySupport.
Back

4. Which NDMP authentication methods are used by DPX?

DPX supports:
NDMP_AUTH_TEXT        User and password information is unencrypted.
NDMP_AUTH_MD5         User and password information uses key-to-the-hash encryption
      (MD5 also referred to as ‘challenge’ mode).

The authentication type used by DPX must match that used by NetApp storage system.
When scanning an NDMP node, DPX (NDMPC) by default attempts to use MD5 (Challenge) authentication initially, the NDMPC falls back to "text" mode authentication if it determines that it could not get the MD5 challenge.

Back

5. How do I set NDMP authentication methods for the NetApp storage system?

To see the current authentication method, use the following command from the NetApp storage system:
nss> options ndmpd.authtype

This shows if it’s set to challenge mode or plaintext mode. In order to set authentication to both plain text and challenge, perform the following commands:

nss> options ndmpd.authtype plaintext,challenge
nss> options ndmpd.enable off
nss> options ndmpd.enable on

Back

6. Is SCSI reservation supported on the NetApp storage system?

ONTAP 7.x release onward supports SCSI Reserve/Release commands for Shared Storage devices, which allows users to dynamically share tape devices with NDMP backup policies.

Back

7. How do I set SCSI reservation on the NetApp storage system?

To enable the SCSI Reserve/Release commands, run

options tape.reservations scsi

To disable it, run

options tape.reservations off
(“off” is default)

Details about the SCSI reservation can be found at the main page, go to http://now.netapp.com/NOW/knowledge/docs/ontap/rel801/html/ontap/cmdref/man1/na_options.1.htm.

Back

8. What is recommended setting for the NetApp storage system with teamed NICs?

9. How do I enable NDMP debug logging on the NetApp storage systems?

NetApp storage systems by default have the NDMP logging turned off. To enable it, go to the prompt, type,
ndmpd debug nn
where nn specifies debug level from 0 - 70; default value is 0
•Level 0 : Turns off debugging
•Level 10 : Displays NDMP connection info
•Level 30 : Level 10 + displays actual NDMP messages and NDMP errors
•Level 50 : Level 30 + displays environment variables and NDMP exceptions
•Level 70 : Level 50 + displays SCSI Command descriptor blocks (CDBs) [recommended for debugging Drive problems]
Back

10. Where are the NDMPD logs located?

The logs are located at /etc/log and exist as ndmpdlog.yyyymmdd (date).
The information in the ndmpdlog is a trace of the NDMP protocol messages as defined in the various versions of the NDMP Protocol Specification.
If logging to files is enabled, a new log file is created each day. The last part of the log file name is the date for which the log file applies. If NDMP sessions are active at the time a new daily log file is created, information for the existing sessions continues to be logged to the file which was active at the time the sessions were created. Information for any new sessions is logged in the new log file. Up to nine daily log files are retained on the system. A log file for a particular day may not exist if NDMP activity does not occurred on that day. Log files over eight days old are automatically deleted by Data ONTAP.
Back

11. How do I enable/disable NetApp SnapMirror logging on to NetApp storage systems?

The following command can be used to enable/disable NetApp SnapMirror logging:

options snapmirror.log.enable on (or off)
On NetApp storage systems, the default setting for NetApp SnapMirror log is turned on. All NetApp SnapMirror activities of the NetApp storage systems are recorded in this log file.

Back

12. What is the location of the NetApp SnapMirror log on NetApp storage system?

The NetApp SnapMirror log file can be found at /etc/log on the root volume of both the source and destination NetApp storage systems.

When NetApp SnapMirror logging is enabled, the log is refreshed weekly in a rotating scheme. Every Sunday at midnight, /etc/log/snapmirror is moved to /etc/log/snapmirror.0, /etc/log/snapmirror.0 is moved to /etc/log/snapmirror.1, and so on with the suffix can go up to 5. This process is called rotation and the NetApp SnapMirror log entries are saved for a total of six weeks.
For more details of this log, go to
ONTAP 7: http://now.netapp.com/NOW/knowledge/docs/ontap/rel723/html/ontap/cmdref/index.htm
ONTAP 8: http://now.netapp.com/NOW/knowledge/docs/ontap/rel801/html/ontap/cmdref/index.htm
Back

13. Where are the A-SIS logs located?

The A-SIS log (deduplication log file) can be found at /etc/log/ with the file names as sis, sis.0, sis.1, sis.2, sis.3, sis.4, and sis.5. The current log file is sis.

Back

DPX Configuration

14. What ports are used for NDMP backup/restore?

Default NDMP port is 10000. For information about port usage, read knowledge base article .
Back

15. How do I scan NetApp storage system into DPX Enterprise?

In the management console, go to Configure/Enterprise, add a new NDMP node to a node group.
For more information about adding a new NDMP node to a node group, see the DPX Configuration Guide, DPX Reference Guide, or DPX Reference Guide on MySupport.
Back

16. How do I identify tape drives attached to the NetApp storage system?

At the command prompt, on the NetApp storage system, run ‘sysconfig –t’ to get the list of tape or should it be storage device now devices with device name (aka device ID). Always use the no-rewind device id nrst#a with DPX.
Also, the NetApp storage system command “storage show tape” provides the device name and unique ID (device serial number).
For more information about configuring the device using the DevConfWizard, see the DPX Installation Guide, DPX Configuration Guide, or DPX Reference Guide on MySupport.
Back

17. How do I test tape drives attached to the NetApp storage system?

Native commands (“mt”) can be used to validate locally attached tape drives on NetApp storage systems.
With a tape loaded into the tape drive, the system mt command can be used to test the functionalities of the device is this storage device.
Run the following commands from the NetApp storage system:
mt { -f | -t } tape_device_id command [count]
For details about mt usage, type ‘man mt’ at the command prompt on the NetApp storage system.
Back

18. How do I identify the tape library arm attached to the NetApp storage system?

Run the following commands from the NetApp storage system:
sysconfig –m - lists media changer device name (aka controller id in DPX)
storage show mc - provides device name and unique ID
Back

19. Can the same media be used for NDMP and non-NDMP backups?

Yes, DPX can store both NDMP and non-NDMP backup data on the same media.
It is strongly recommended to use different a media pool for NDMP and non-NDMP backups.

Back

20. Is hardware encryption supported for NDMP backup?

Currently, hardware encryption is supported for the tape drives locally attached to the NetApp storage system for specific drives. See the DPX Operations Guide, DPX User’s Guide, or DPX Reference Guide on MySupport.
For the latest system requirements and compatibility details regarding supported hardware, file systems, applications, operating systems, and service packs, go to http://mysupport.catalogicsoftware.com/content/DPXcompat.pdf
Back

21. Is software encryption supported for NDMP backup?

Currently, software encryption is not supported for NDMP backups.

Back

DPX Backup

22. What is a DUMP mode backup?

DUMP is a backup method used for data transfer. For more information about NDMP backup options, see the DPX Operations Guide, DPX Reference Guide, or DPX Reference Guide on MySupport.

Back

23. What is SMTAPE mode backup?

SMTAPE method is backup method used in a block-level image of the source volume. If DR guideline requires a full volume restore, rather than individual files and folders, the SMTAPE backup method is preferred over the dump method. For information about SMTAPE mode backup, read knowledge base article NDMP Backups: dump vs. smtape

Back

24. What is the difference between the dump and smtape types of backup?

The primary difference is DUMP backup allows file level restores whereas SMTAPE backup allows only full volume restore. For more detail, read knowledge base article NDMP Backups: dump vs. smtape

Back

25. What are the supported NDMP backup configurations?

The NDMP backups can be performed using tape drive locally attached to the NetApp storage system (local backup), tape drive attached to Server node (NetApp Storage System to Server backup) or another NetApp storage system (NetApp Storage System to NetApp Storage System backup).
For more information about the supported NDMP backup configurations, see the DPX Operations Guide, DPX User’s Guide, or DPX Reference Guide on MySupport.

Back

26. What is file history?

The file history entries provide a file by file record of every backed up file. File history is also saved in the Catalog and used during the restore time.
Back

27. Why do we need file history?

While backup definition can include an entire node or volume, file history allows the restoring individual files.

Back

28. How do I enable data encryption for NDMP backup?

In the management console, go to Backup / NDMP, define the backup. To enable the encryption, click Set Encryption Options, change the default setting ‘No Data Encryption’ to ‘Encrypt Data at the device server (primary tape only) and select a keyring.
For more information about the NDMP data encryption option, see the DPX Operations Guide, DPX User’s Guide, or DPX Reference Guide on MySupport.
For more information about how to define and use keyrings, see the DPX Configuration Guide, DPX Reference Guide, or DPX Reference Guide on MySupport.

Back

29. Can I perform an NDMP backup for the Catalog?

No, at this time Catalog backup is supported only through the Catalog Backup job.
Back

30. What is the format used to write NDMP data on tape?

DPX writes NDMP data to tape in DUMP format.
Back

31. Are BASE/DIFR/INCR schemes fully supported for NDMP backups?

NDMP DUMP method of backup supports base, differential, and incremental backup schemes; files modified from last backup are included in current backup. SMTAPE backup ignores these options and always run a full volume base backup.

Back

32. What are the limitations of NDMP type backup/restore?

At this time, NDMP backup does not include a backup verification option, performance option, or tape mode restore feature available for the File type jobs.
For more information about the limitations of NDMP backup/restore, see the DPX Operations Guide, DPX User’s Guide, or DPX Reference Guide on MySupport.
Back

33. Is there any limitation on source volume or file size?

It is only limited by the operating system of the source nodes.
Back

34. Can additional NDMP parameters be passed to backup/restore job definition?

Yes. For more information about the additional NDMP parameters to be passed to the backup/restore job definition see the DPX Operations Guide, DPX Reference Guide, or DPX Reference Guide on MySupport.

Back

DPX Restore

35. What is NDMP Extract mode restore?

During Extract mode, the restore job mounts and sequentially reads all tapes used during the backup.
If the NDMP backup is performed with file history disabled, the NDMP restore must be performed with the NDMP Recover Mode under ‘Destination Options’ set to Extract.
The NDMP restore will fail with message “ssndmpc closed connection” if the NDMP Recover Mode under ‘Destination Options’ is to set to Direct instead of Extract.
For more information about NDMP restore options, see the DPX Operations Guide, DPX Reference Guide, or DPX Reference Guide on MySupport.
Back

36. What is NDMP Direct Access Restore?

Direct Access Restore is a facility within NDMP that significantly improves restore performance of individual files. Using Direct Access Restore and DPX, only the tape which contains the file is mounted. DPX fast forwards the tape to the exact location of the file and executes the restore. Without Direct Access Restore, DPX must mount and sequentially read all tapes using during the backup.

Back

37. Can I restore individual files?

Yes, both the Extract and Direct methods can restore individual files. The Direct method can significantly increase restore speed, but it requires the DAR option being enabled on the NetApp storage system and file history is enabled in the backup.

DAR provides performance improvements (Data ONTAP 6.4 or later). Enhanced DAR during restore is possible only if the following conditions are met:

The ‘ndmpd.offset_map.enable’ option on NetApp storage system is set to "on".

From the NetApp storage system console type: “options ndmpd.offset_map.enable on”
Enable this functionality before you initiate the NDMP dump operation, before backup job.

“NDMP File History Handling” option is set to ‘Local Client’ or ‘Master Server’ in backup Job Source Options in DPX during the backup.

(This option is setting environment variable (HIST=Y) which is supported by Data ONTAP)

“NDMP Recover Mode” is set to ‘Direct’ in restore Job Destination Options in DPX during the restore.

(This option is setting environment variable (ENHANCED_DAR_ENABLED=Y) which is supported by Data ONTAP)

Back

38. Is tape mode restore supported for NDMP?

Tape mode restore is not available for NDMP data.
The Tape mode restore is a feature that enables restore of the data directly from the tape without references to the Catalog.
Back

39. Can multiple folders be selected in the NDMP backup job definition?

If more than one folder is selected in the job definition, the parent folder is backed up by the NDMP backup.
Back

40. How do I restore from encrypted tapes with NDMP backup?

Running an NDMP restore from encrypted tapes is similar to any other restore:

1.	On the management console Function Tab Bar, select Restore. On the Sub-tab Bar, select NDMP.

2.	In the SOURCES pane, select a backup instance.

3.	In the DESTINATIONS pane, select a destination

4.	On the Task Panel, select Run or Run and Monitor.

DPX reads the keyring from the tape volser (volume label) and the tape is automatically decrypted for restore.

Warning: When a restore job completes, DPX resets the decryption key in the tape drive, making the tape secure. However, a system disruption, such as intentional or unintentional loss of communication or hardware fault, may prevent resetting the key. In this case, the tape remains in the tape drive, but the encryption key is not reset. This condition leaves the tape in a state where reading unencrypted data is possible by someone who has access to the NDMP storage system to which the drive is attached. To resolve the error condition, eject the tape from the tape drive. This resets the decryption key. In all cases where the return code of an NDMP hardware encryption restore job is not 0, it is advisable to take steps to ensure security of the restore tape.

Back

41. How do I set up an NDMP Tape Library with DPX?

For information about setting up a tape library, read knowledge base article Configuring Tape Library Connected to NetApp Storage

Back

NDMP FAQ