Host Groups and Pairing
Host Groups and Pairing
This page covers two related ways of managing multiple hosts together: grouping hosts that should share the same volume mappings (useful for clusters), and pairing a host or host group with its counterpart on a remote system for replication.
Host groups
A host group lets you map volumes to several hosts at once — useful for a cluster where every node needs the same LUNs, since you map the volume to the group instead of mapping it to each host individually. A host group is made up of existing hosts; a host can only belong to one group at a time.
Creating a host group
Using the web interface
- Open Application Volumes > Hosts and choose Create Group.
- Under Name, enter the group's name.
- Under Grouped Hosts, choose the hosts that belong to the group.
- Confirm to create the group.
Using the CLI
hosts create_group --name=<name> --groupedHosts=<name...>
| Option | Description |
|---|---|
--name=<name> |
The name of the new initiator/host group. |
--groupedHosts=<name...> |
The names of the initiators/hosts belonging to the group. |
Example
hosts create_group --name db-cluster --groupedHosts db-server1 db-server2 db-server3
Adding or removing hosts from a group (CLI only)
A shortcut for changing a group's membership incrementally, without having to restate the whole member list via hosts edit.
hosts add_to_group --name=<name> --groupedHosts=<name...>
hosts remove_from_group --name=<name> --groupedHosts=<name...>
| Option | Description |
|---|---|
--name=<name> |
The name of the host group. |
--groupedHosts=<name...> |
List of hosts to add to or remove from the group. |
Examples
Add a fourth node to the cluster's host group:
hosts add_to_group --name db-cluster --groupedHosts db-server4
Remove a node that's being decommissioned:
hosts remove_from_group --name db-cluster --groupedHosts db-server2
Pairing hosts for replication
Pairing links a local host (or host group) to a host (or host group) on a remote StorONE system, so that when a volume is replicated to that remote system, StorONE already knows which remote host should receive the mapping — you don't have to reconstruct the host mapping by hand after a failover. A host group can only be paired with another host group, and every host inside it must have a matching counterpart (by name, WWPN, IQN, or NQN) in the remote group.
A host that's already part of a host group can't be paired or unpaired individually — pairing is done for the whole group at once.
Pairing a host
Using the web interface
- Open Application Volumes > Hosts, select the host (or host group), and choose Pair.
- Under Local Host, confirm the host being paired.
- Under Target Host, choose the target system and the target host on that system.
- Confirm to create the pairing.
Using the CLI
hosts pair <name> --targetSystem=<name> --targetHost=<name>
| Option | Description |
|---|---|
<name> |
The local host or host group to pair. |
--targetSystem=<name> |
The remote system to pair with. |
--targetHost=<name> |
The host or host group on the remote system to pair with. |
Example
hosts pair db-server1 --targetSystem dr-site --targetHost db-server1-dr
Unpairing a host
Using the web interface
- Open Application Volumes > Hosts, select the paired host (or host group), and choose Unpair.
- Under Target Host System, confirm the remote system to unpair from.
- Confirm to remove the pairing.
Using the CLI
hosts unpair <name> --targetSystem=<name>
| Option | Description |
|---|---|
<name> |
The local host or host group to unpair. |
--targetSystem=<name> |
The remote system to unpair from. |
Example
hosts unpair db-server1 --targetSystem dr-site
See also: Hosts