NDMP backups - What triggers an Incremental versus a Full backup ?

NDMP backups - What triggers an Incremental versus a Full backup ?

Article: 100003583
Last Published: 2010-11-04
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Product(s): NetBackup


NDMP backups - What triggers an Incremental versus a Full backup ?



For NDMP backups, The NAS server is issuing it's own backup command to back up the server data.
The NAS server is in complete control of what files and metadata is backed up since it is using it's own backup process. (dump/tar)

Here are the dump levels issued By NetBackup to the NAS server
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NetBackup backup types  NDMP backup levels
NetBackup Full                 NDMP level 0
NBU Cumulative               NDMP level 1
NetBackup Diff                 NDMP level (last level + 1, up to 9) never goes higher than 9




You can see the NDMP backup level that was issued and the NAS dump progress updates of the backup by issuing the vxlogview command on the master server
      #  /usr/openv/netbackup/vxlogview -i ndmpagent -d T,s,x,p -t 8      (-t  8   =  last 8 hours )

Examples for NetApp Filer:
When a Full backup is scheduled from NetBackup master, the Filer is issued a  Level 0 'Dump' of it's filesystem and the OS delivers all files to the filer dump process to be sent to the designated storage. The file list is sent to the NetBackup master for cataloging for later browsing for restores.


NetApp Filer Dump Command Info

For Incremental, the NetApp Filer Dump process uses /etc/dumpdates file on the NAS server to figure out which files it needs to back up when doing incremental backups. Incremental Dump will back up all files that have been modified (or had other attributes changed), since the most recent backup at a lower dump level.

NetApp Filer  /etc/dumpdates Info



Contact the NAS vendor for more specifics on the  'Dump'  process
If incrementals for the NAS server are not working properly, the vendor should be contacted to verify the NAS server has the latest updates and to test the dump process manually.

Commands commonly used for quick filesystem read on NetApp Filer to /dev/null without dumping to device.
         Filer> dump 0f null /vol/vol0
         Filer> dump 1f null /vol/vol0
Then view the NetApp Filer   /etc/log/backup   and      /etc/dumpdates

NDMP / Backup logging:

NetApp Filer:
      /etc/messages                     (Hardware log)
      /etc/log/backup                    (DUMP Backup log)
      /etc/dumpdates                    (Log of file system dump times)
      /etc/log/ndmpdlog.<date>    (NDMP Log) (Missing by default. Disable after backup test is completed since it may create space issues if unattended.)
               To enable the NDMP log, run filer command:  Filer> ndmpd debug 50
               To disable the NDMP log, run filer command:  Filer> ndmpd debug 0


NetApp Data Protection Tape Backup and Recovery Guide  No. 210-04162_A0

Checking the status of a (NetApp) dump backup
During a lengthy dump session, you are advised to monitor the progress and check the status of the
session. This helps you to check if the backup is proceeding as expected.

1. To check the status of a dump command, enter the following command:
stat show dump  

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