Source:Troubleshooting NDMP

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Docs latest icon.png Welcome to the latest SEP sesam documentation version 4.4.3 Beefalo/5.0.0 Jaglion. For previous documentation version(s), check documentation archive.


NDMP

NDMP connection error during backup

Problem

  • The NDMP server fails to connect to SEP sesam (sbc_ndmp) during an NDMP backup. Errors like the following are displayed and the backup fails.
  • NDMP error: ERR NDMP4_DATA_CONNECT NDMP4_CONNECT_ERR NDMP error: ERR NDMP4_DATA_ABORT NDMP4_ILLEGAL_STATE_ERR or NDMP error: NDMP_DATA_CONNECT

Possible causes

  • In most cases, this is a firewall problem.
  • Other incorrect network settings prevent the connection to sbc_ndmp.
  • In the case of NetApp, multiple interfaces may prevent the connection to sbc_ndmp.

Solution

  • Exclude sbc_ndmp.exe from the firewall scanner and run the backup again.
  • Check the configuration of your network. Note that your network must be configured correctly to allow the connection to sbc_ndmp.
  • In the case of NetApp, if multiple interfaces are suspected, set the preferred interface option on your NAS device to specify the interface which should be used for NDMP:
  • options ndmpd options ndmpd.preferred_interface <interface_name> For more details, see NetApp-specific NDMP configuration.

NDMP restore to new restore target with non-existent subdirectory fails

Problem

  • An NDMP restore to a new restore target where the intended restore target is a different, non-existent subdirectory fails. (In previous SEP sesam versions, the NDMP alternate restore to a non-existent subdirectory fails, but it is shown as successful. Although this is now fixed, you may want to verify that the previously restored NDMP data exists.)


Note that this is only the case if the new restore target is a non-existent subdirectory. For example, if you want to restore to a /<volume_name>/<sub_dir1>/<sub_dir2> and <sub_dir1> does not exist, the restore will fail. You can still restore NDMP to the alternative target subdirectories if they already exist.

Cause

  • If a subdirectory is specified as the new (non-existing) restore target, for example, /<volume_name>/<sub_dir1>/<sub_dir2>, the restore fails as non-existing subdirectories are not supported when restoring to another target. In this case, only a single level directory structure can be used as the restore target: /<volume_name>/<target_dir>; so in the above example, the supported restore target path is /<volume_name>/<sub_dir1>.

Workaround

  • When performing an NDMP restore to a new restore target, make sure that you restore your data to the top-level directory (/<volume_name>/<target_dir>). Do not specify any non-existing subdirectories in the new target path, otherwise the restore will fail.

Selective NDMP restore does not restore empty directories and the restore fails

Problem

  • In SEP sesam versions ≤ 4.4.3 Beefalo V2, when performing a selective NDMP restore, empty directories are not restored (created) on the target if:
    • empty directories are present in the restore list along with normal directories and files (this is a known issue, but too minor to warrant a fix)
    • at least one file is selected in another directory, for example, if the backup source is /vol/vol1 and the restore selection is /vol/vol1/dir_1/file_1 and /vol/vol1/empty_dir

Consequently, the restore fails.

Cause

  • If only directories are selected for selective restore, the empty directories are added to the SEL file by sm_restore and the restore completes without error. However, if at least one file is selected together with an empty directory, the restore fails.

Workaround

  • When performing a selective restore, try not to restore empty directories together with individual files, otherwise the restore will fail.

NDMP on NetApp

NDMP browsing of non-UTF-8 fails and restore to non-UTF-8 volume may not be possible

Problem

  • When performing a restore, it is not possible to browse the contents of non-UTF-8 NetApp volumes. You may receive an error message similar to the following:
NDMP error:  ERR NDMP4_SNAP_DIR_LIST  ?0x20500106?

This can happen because:

  • Non-UTF-8 volumes are not searchable if objects contain umlauts or special characters.
  • Consequently, a restore to a non-UTF-8 volume is not possible if objects with special characters are included in the NDMP backup.

The following ONTAP CLI command displays the encoding language of all volumes:

volume show -vserver * -fields language

Solution

  • NDMP backups of NetApp volumes without UTF-8 encoding language are basically possible, but the path in the backup task can only be specified manually.
  • If a backup of a non-UTF-8 volume contains objects with umlauts or special characters, the restore can only be performed to a UTF-8 volume.

NDMP DAR restore of single files is too slow

Problem

  • When using a Direct Access Recovery (DAR) which enables NDMP selective restore, restore is too slow, even though DAR should greatly reduce the time it takes to restore individual files.

Cause

  • The general prediction is that DAR greatly increases restore speed, but this depends on the amount and size of data backed up. As stated by NetApp, the restore can take quite some time depending on the number of files in the directory, the position of the directory and file on the tape, and the number of tapes to be read. Refer to the NetApp documentation for details.

Solution

  • Split the backup into smaller parts to reduce the amount of information that DAR has to manage during the restore.

Restore fails with: "Storing of nlist entries failed."

Problem

  • Restore finishes with the error message: "Storing of nlist entries failed."

Workaround

  • Instead of commonly used version 4 of the NDMP protocol, start the NDMP daemon in version 3 by entering the following commands:
  • ndmpd off ndmpd version 3 ndmpd on
  • Then retry the NDMP restore.

See also

Analyzing SEP sesam Log FilesNetApp-specific NDMP configurationNDMP