User guide

The oneSIS method also configures a central read-only root file system on the NFS server. But
instead of writing back to the NFS server, the oneSIS software configures a local read-writable
tmpfs file system on each diskless client, copies the read-writable files into that file system, and
makes the appropriate soft links from the read-only root file system into this read-writable tmpfs file
system. The result is that all file reads are done from the NFS server, but the file write activity occurs
in local memory.
The advantage of the system-config-netboot method is that all node write activity is preserved
on the NFS server. All node write activity on the oneSIS method occurs in local memory by default,
and can be lost if the node is rebooted. If the user implements the oneSIS method and has write
activity that they would like to preserve, then they must configure a separate NFS location to store
this write activity.
The advantage of the oneSIS method is improved performance of any write activity (because it
goes to local memory rather than over the network to the NFS server) and less network traffic to
the NFS server. Also, because the diskless clients do not store any state on the NFS server, NFS
server failover can be accomplished by simply failing over one NFS server to another. With the
system-config-netboot method, a high-availability NFS server solution requires shared
storage between the primary and backup NFS server so that the node state is preserved through
an NFS server failover scenario.
Another advantage of the oneSIS method is that there is no requirement for the HP Insight CMU
management node and the golden node to run the same OS version. This is a requirement for the
system-config-netboot method. With the oneSIS method, you can deploy different diskless
OS versions from a single HP Insight CMU management node.
The system-config-netboot method is described in “The system-config-netboot diskless
method”. The oneSIS method is described in “The HP Insight CMU oneSIS diskless method”. Scaling
out either diskless method across multiple NFS serves is discussed in “Scaling out an HP Insight
CMU diskless solution with multiple NFS servers”
5.8.1.1 Enabling diskless support in HP Insight CMU
Regardless of which diskless method you choose to use, you must enable diskless support in HP
Insight CMU first.
1. Edit /opt/cmu/etc/cmuserver.conf to activate CMU_DISKLESS:
#cmu diskless feature true/false
CMU_DISKLESS=true
5.8 HP Insight CMU diskless environments 69