A VxFS file system mounted with the
cluster option is a cluster, or shared, mount, as opposed to a non-shared or local mount. A file system mounted in shared mode must be on a VxVM shared volume in a cluster environment. A local mount cannot be remounted in shared mode and a shared mount cannot be remounted in local mode. File systems in a cluster can be mounted with different read/write options. These are called asymmetric mounts.
Asymmetric mounts allow shared file systems to be mounted with different read/write capabilities. One node in the cluster can mount read/write, while other nodes mount read-only.
You can specify the cluster read-write (
crw) option when you first mount the file system, or the options can be altered when doing a remount (
mount_vxfs(1M) manual page.
Primary and secondary mounts describes the first column in the following table shows the mode in which the primary is mounted:
The check marks indicate the mode secondary mounts can use.
Mounting the primary with only the
-o cluster,ro option prevents the secondaries from mounting in a different mode; that is, read-write.
rw implies read-write capability throughout the cluster.