Asymmetric mounts allow shared file systems to be mounted with different read/write capabilities. So 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 (
remount). 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.
Primary and secondary mounts describes the first column in the following table shows the mode in which the primary is mounted:
Only mounting the primary with
cluster,ro prevents the secondaries from mounting in a different mode, that is, read-write mode. Note that
rw implies read-write capability throughout the cluster.
mount_vxfs(1M) manual page.