Create and Maintain Volume Dump File

Describes how to create full dump files and add incremental volume dump files.

You can use volume dump create to create two types of files:

  • full dump files containing all data in a volume
  • incremental dump files that contain changes to a volume between two points in time

A full dump file is useful for restoring a volume from scratch. An incremental dump file contains the changes necessary to take an existing (or restored) volume from one point in time to another. Along with the dump file, a full or incremental dump operation can produce a state file (specified by the ?-e parameter) that contains a table of the version number of every container in the volume at the time the dump file was created. This represents the end point of the dump file, which is used as the start point of the next incremental dump. The main difference between creating a full dump and creating an incremental dump is whether the -s parameter is specified; if -s is not specified, the volume create command includes all volume data and creates a full dump file. If you create a full dump followed by a series of incremental dumps, the result is a sequence of dump files and their accompanying state files:

dumpfile1 statefile1

dumpfile2 statefile2

dumpfile3 statefile3

Note: You can restore the volume from scratch, using the volume dump restore command with the full dump file, followed by each dump file in sequence.

When you create a dump file for a volume enabled for data at rest encryption, data in the dump file is not encrypted.

Note: In a secure cluster, you must use the MapR user ID. Using root or any other user ID results in the system hanging.

To create and maintain an up-to-date dump of a volume:

  1. Create a full dump file.
    maprcli volume dump create -name cli-created -dumpfile fulldump1 -e statefile1
  2. Periodically, add an incremental dump file.
    maprcli volume dump create -s statefile1 -e statefile2 -name cli-created -dumpfile incrdump1 maprcli volume dump create -s statefile2 -e statefile3 -name cli-created -dumpfile incrdump2 maprcli volume dump create -s statefile3 -e statefile4 -name cli-created -dumpfile incrdump3
    ...and so on.