Creating Remote Mirrors
Describes the use of remote mirror volumes. The remote mirror volume is present on a different cluster from the source volume.
Creating remote mirrors is similar to creating local mirrors, except that the mirror volume
resides in a different cluster from the source volume. To properly identify the source
volume, you must specify the source cluster name when the mirror volume is created. In
addition, you must edit the mapr-clusters.conf
file so that each cluster
can resolve the nodes in the other cluster.
To create a mirror on a remote cluster, you must have the same UID for the
MAPR_USER
(the cluster owner) for both the primary cluster (where the
source volume resides) and the remote clusters (where the mirror volumes reside; also known
as the destination clusters). You also need to have the following volume permissions:
-
dump
permission on the source volumes -
restore
permission on the mirror volumes at the destination clusters
When a mirror volume is created on a remote cluster (according to the entries in the
mapr-clusters.conf
file), the CLDB checks that the local volume exists
in the local cluster. If both clusters are not set up and running, the remote mirror volume
cannot be created.
To summarize:
- Each cluster must be already set up and running.
- Each cluster must have a unique name.
- Every node in each cluster must be able to resolve all nodes in remote clusters, either
through DNS or entries in
/etc/hosts
. - The UID for the
MAPR_USER
(cluster owner) must be the same for the source and destination clusters, irrespective of which user account triggers the mirror operation. - Volume permission must be set to
dump
on the source volumes. - Volume permission must be set to
restore
on the mirror volumes.
See also: Remote Mirroring.