By default, a volume in disk groups with the FSS attribute set is mirrored across hosts. This default layout ensures that data is available if any one host becomes unavailable. Associated instant data change object (DCO) log volumes are also created by default.

You can specify the hosts on which to allocate the volume by using the host disk class.

See Using the host disk class and allocating storage.

Traditionally with disk groups without the FSS attribute set, the default volume layout is concatenated. However, you can still choose to create concatenated volumes in disk groups with the FSS attribute set by explicitly using the layout=concat option of the vxassist command.

By default, the mirrored volume is allocated across hosts. If host-specific storage is not available to meet this criteria, then the volume is allocated on external storage, with the default layout as concatenated as with traditional disk groups.

Existing disk classes, such as dm, can be used with FSS. The host prefix in a disk access name indicates the host to which the disk is connected.

For example, you can create a volume with one plex on a local disk (disk1), and another plex on a remote disk(hostA_disk2) where the host prefix (hostA) for the remote disk represents another host in the cluster:

# vxassist -g mydg make vol1 10g layout=mirror dm:disk1 dm:hostA_disk2

See Administering mirrored volumes using vxassist.

You can also use the vxdisk list accessname command to display connectivity information, such as information about which hosts are connected to the disk.