EMCMD <system> CHANGEMIRRORTYPE <volume letter> <remote ip> <A/S>

This command is used to change the mirror type of a mirror that is part of a DataKeeper job.

Note: The volume must be online.

Refer to the examples below.

See Synchronous and Asynchronous Mirroring for information about the supported DataKeeper mirror types.

<system> The source or target system on which to initiate the changing of the mirror type.
<volume letter> The drive letter of the mirror to be changed.
<remote IP> The IP address of the remote system.
<A/S> The new mirror type (Asynchronous or Synchronous).


  • A job may contain multiple volumes and multiple mirrors. The CHANGEMIRRORTYPE command will modify the type of one mirror each time it is used.

  • The volume must be online on each system in the mirror to change the mirror type of an existing mirror.

  • The mirror type of an existing mirror can be changed while the mirror is in the active Mirroring state. The type change takes effect immediately.

  • The mirror type of non-existing mirrors can be changed. See the 1×1×1 example below.

  • The mirror type of a mirror that is in the Split-Brain state cannot be changed – the Split Brain must be resolved first.

  • If a job contains multiple mirrors, individual mirror types can be modified. Having mixed mirror types within a job, and within the mirrors for an individual volume in the job, is supported.

1×1 Mirror CHANGEMIRRORTYPE Command Example

emcmd SYS1.MYDOM.LOCAL getJobInfoForVol D

ID = caa97f9f-ac6a-4b56-8f25-20db9e2808a8

Name = Mirr Vol D

Description = Mirror Volume D


emcmd SYS1.MYDOM.LOCAL ChangeMirrorType D S

The above example changes the mirror of D: between SYS1 and SYS3 to Synchronous.

1×1×1 Mirror CHANGEMIRRORTYPE Command Example

emcmd SYS1.MYDOM.LOCAL getJobInfoForVol J

ID caa97f93j-ac6a-4b56-8f25-20db9j2808a8

Name = Mirr Vol J

Description = Mirror Volume J




emcmd SYS1.MYDOM.LOCAL GetMirrorVolInfo J



emcmd SYS1.MYDOM.LOCAL ChangeMirrorType J S

emcmd SYS1.MYDOM.LOCAL ChangeMirrorType J S

emcmd SYS2.MYDOM.LOCAL ChangeMirrorType J S

In this example, all mirror types will be changed to Synchronous. The third command changes the mirror type of the non-existing mirror between SYS2 and SYS3.


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David Allen Bermingham wrote: Jun 16, 2021

Does this work with a 2 x 1 mirror? If so we need an example. If not, we need to document that.