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Many of the actions that are described are available from different menus. For example, you can select Volumes  and its option Volumes by Hosts , where you can also rename hosts. This flexibility is one of the advantages of the enhanced, redesigned IBM Spectrum Virtualize management GUI. 

## 3.5.2 Host clusters 

A host cluster is a group of logical host objects that can be managed together. For example, you can create a volume mapping that is shared by every host in the host cluster (see Figure 3-64). 

<img src='content_image/998893.jpg'>

The systems use internal protocols to manage access to the volumes and ensure consistency of the data. Host objects that represent hosts can be grouped in a host cluster and share access to volumes. New volumes can also be mapped to a host cluster, which simultaneously maps that volume to all hosts that are defined in the host cluster. Each host cluster is identified by a unique name and ID, the names of the individual host objects within the cluster, and the status of the cluster. 

A host cluster can contain up to 128 hosts. However, a host can be a member of only one host cluster. The management GUI displays the status of each host cluster. 

A host cluster can have one of the following statuses: 

GLYPH<SM590000> Online: All hosts in the host cluster are online. 

GLYPH<SM590000> Host degraded: All hosts in the host cluster are online or degraded. 

GLYPH<SM590000> Host cluster degraded: At least one host is offline and at least one host is online or degraded. 

GLYPH<SM590000> Offline: All hosts in the host cluster are offline (or the host cluster does not contain any hosts). 

