Setting the Topology for Local Volume Replicas
Explains how to set the topology for local volume replicas using the CLI.
About this task
The primary copies for containers of local volumes are placed on the local node
(specified with parameter -localhost
in the volume
create
command). The nodes for the replica copies for containers of
local volumes are chosen as follows:
Procedure
-
If a topology is explicitly specified for replicas during
volume create
orvolume edit
, that topology will be used.
In the above example, the primaries for the volume are placed on node 10.20.30.40, and replicas will be placed on nodes in the topology /rack1/test.maprcli volume create -name egLocalVol -path /test/local/volumes/examples/sample1 \ -localvolumehost 10.20.30.40 -topology /rack1/test
The
-topology
parameter is optional, and if it is not specified, CLDB will fall back to 2 or 3 below. -
If the configuration parameter that specifies a relative path for replicas of
local volumes is set, that will be used.
This will trim the topology of the node specified by the localhost parameter and restrict the replicas to the resultant topology.maprcli config save -values {"cldb.local.volume.topology.trim.index":"-1"}
By default, this configuration parameter is not set. To set this configuration parameter, see Creating Replicas of Local Volumes in Custom Topology Using the CLI. If the configuration parameter is not set, CLDB will fall back to 3 below.
-
The default volume topology will be used.
The default volume topology is the value specified by the configuration parameter
cldb.default.volume.topology
. The default value for this parameter is/data
. See Setting Default Volume Topology Using the CLI.