Glossary

This glossary explains the terms used in the MCS for the different types of volumes. A sample display from the Type column is shown here:



Term Definition
NC Standard Volume

A non-convertible standard volume with read-write capabilities, created before MapR version 4.0.2. These volumes cannot be converted to standard mirror volumes. If this volume type is designated as a source volume when a mirror volume is created, the mirror volume will be an NC mirror volume.

When you move the mouse over the NC Standard Volume text in the MCS, the following tooltip is displayed:

An NC standard volume is designated as type 0 in the output of the volume info command. For example:

maprcli volume info -name oldrw

lists

“mirrortype”:0

Standard Volume A read-write volume created with MapR version 4.0.2. A standard volume can be converted from read-write to mirror (read-only). If a mirror is created from this type of volume, the mirror can be promoted to a read-write volume.

A standard volume is designated as type rw on the command line. For example:

maprcli volume create -name volA -path /testvol -type rw

NC Mirror Volume

A non-convertible read-only mirror volume created before MapR version 4.0.2. This volume type cannot be promoted to a read-write volume, and can only be created from an NC standard volume.

When you move the mouse over the NC Mirror Volume text in the MCS, the following tooltip is displayed:

An NC mirror volume is designated as type 1 in the output of the volume info command. For example:

maprcli volume info -name oldmirror

lists

“mirrortype”:1

Standard Mirror

A mirror volume that starts as read-only, and can be promoted to a read-write volume.

A standard mirror volume is designated as type mirror on the command line and can only use a standard volume as its source. For example:

maprcli volume create -name volB -path /mirvol -type mirror -source volA