Serviceguard NFS Toolkit A.11.11.06, A.11.23.05 and A.11.31.08 Administrator's Guide (October 2011)

12th Edition. To locate this document, go to the HP-UX Serviceguard docs page at:
www.hp.com/go/hpux-serviceguard-docs. On this page, select HP Serviceguard.
Serviceguard A.11.17 is not available on HP-UX 11i v1 systems, so Serviceguard CFS support
is only applicable to HP-UX 11i v2.
Limitations
The following is a list of limitations when using Serviceguard NFS Toolkit A.11.23.05 with
Serviceguard A.11.17:
• Serviceguard A.11.17 introduces a new MULTI_NODE package type which is not supported
by Serviceguard NFS Toolkit. The only supported package type is FAILOVER.
• Serviceguard A.11.17 provides a new package configuration file template. The new package
configuration file template introduces the following dependency variables:
◦ DEPENDENCY_NAME
◦ DEPENDENCY_CONDITION
◦ DEPENDENCY_LOCATION
The above parameters are not supported in Serviceguard NFS Toolkit A.11.23.05. By default,
these variables are commented out in the nfs.conf file.
Integrating Support for Cluster File Systems into Serviceguard NFS Toolkit
In a non-CFS implementation, access to a specific file must go through a single NFS server which
can limit scalability and cause a performance bottleneck. With CFS, files and filesystems may be
accessed concurrently from multiple servers. By integrating CFS into a Serviceguard NFS
environment, files and filesystems can be accessed concurrently from multiple highly available NFS
servers to improve performance, scalability, and availability.
Initial Serviceguard NFS Toolkit support for CFS will be limited in scope, specifically for applications
that require file locking across NFS mounts during a failover. For applications that do not require
file locking during a failover, a DNS round-robin scheme or other load balancing tools may be
used to distribute the load evenly between the servers. Additional support will be phased into future
releases.
Overview of Cluster File Systems in Serviceguard NFS Toolkit
Current SG-NFS over VxFS Support
In a Serviceguard environment, a Serviceguard NFS over VxFS (failover) package is defined as a
collection of resources including relocatable IP addresses and logical volume groups (data disks)
associated with NFS services. If the server on which a package is running fails, then Serviceguard
will automatically start the NFS package on the adoptive node. The adoptive node takes control
of the IP addresses and disks and starts the NFS services.
CFS versus Non-CFS Implementation
Serviceguard A.11.18 (or later) supports CFS which provides data and lock coherency and allows
files and filesystems to be shared and accessed concurrently by multiple servers.
Figure 1–1 shows how files and filesystems are accessed differently in a non-CFS environment
versus a CFS environment. In a non-CFS environment, the highly available filesystems move from
one node to another when there is a failover. The solid lines show which primary node provides
access to which filesystem and the dotted lines show which adoptive node provides access in the
event of a failover. The volumes are exclusively activated only on the server that currently runs the
package, which prevents files and filesystems from being altered concurrently by multiple nodes.
10 Overview of Serviceguard NFS