IBM Hub/Switch Installation Manual

Also see for High Performance Storage System HPSS: Management guide Installation guide

Contents

Chapter 7 HPSS User Interface ConfigurationHPSS Installation Guide September 2002 431Release 4.5, Revision 27.4 NFS Daemon ConfigurationBefore the HPSS NFS daemon can be started, any existing AIX or Solaris native NFS daemonsmust be stopped and prevented from restarting. This is important because the NFS protocol doesnot provide a way for clients to specify which of two daemons is wanted. When the system is setup correctly, there should be no 'nfsd' or 'mountd' processes running. If nfsd was runningbefore, it may be necessary to free up the ports it allocated by using the 'rpcinfo -d' command. Otherwise theHPSS daemon may not start correctly. Also be sure to stop rpc.lockd and rpc.stad. The HPSS NFS daemondoes not support file locking.Additional HPSS NFS configuration information is specified through the HPSS exports file andthrough environment variables. If the default server name for the HPSS LS is not used, theenvironment variable for the LS, HPSS_LS_NAME should be changed in the hpss_env file.Similarly, if the default for the NFS Server descriptive name is not used, the environment variableHPSS_NFS_DESC_NAME should also be changed in the hpss_env file.NFS allows you to traverse junctions, but be aware that certain functions may not behave asexpected after a junction traversal (i.e. “cd ..”). By default, NFS junction traversal is disabled. Toenable it, add HPSS_NFS_ENABLE_JUNCTIONS = “on” to the hpss_env file before bringing upthe Startup Daemon. This environment setting will also allow junctions to be mounted (i.e. “mounthostname:/junction”).HPSS NFS does not support yellow pages (Sun MicroSystems’ Network Information Services) tovalidate hosts. HPSS NFS does provide an option to validate the network address of hostsattempting to mount HPSS directories. The default configuration disables this check. To enable thischeck, define the variable HPSS_MOUNTD_IPCHECK in the hpss_env file.Note: For users who have several NFS clients concurrently updating and reading the HPSSnamespace and depend on having their namespace changes immediately reflected in all clients, itis necessary to perform NFS mounts with the noac option. Here is an example:mount -orw,intr,timeo=30,noac hpssserver:/hpss /hpssUsing the noac option will degrade performance since it prohibits caching. Only use it if NFS clientsrely on immediate HPSS namespace updates.If people are using NFS to mount file systems from several hosts, a situation can develop where oneNFS daemon gets bogged down and then users can't access the other file systems either. This is acommon problem with all NFS file systems and is not peculiar to HPSS. However because the HPSSNFS daemon is prone to bogging down, it is especially likely to affect other file systems.To avoid this problem, sites may want to advise their users on the best way to set up their NFSmount points. All of the mount points for a particular NFS host should be kept in a directoryseparate from the other hosts. (This is probably a good idea even if the clients are not mountingHPSS files.) One convention for doing this is to name the mount points by the name of the host thatis exporting the file system. For example, if a host named tardis is exporting HPSS directories /home and /public, and a host named jupiter is exporting the Unix directory /home, the mountpoints might be: /nfs/tardis/home, /nfs/tardis/public, and /nfs/jupiter/homeIf these names aren't considered user friendly, the site can use symlinks to establish friendliernames. For example, /hpss could point to /nfs/tardis, and /users could point to /nfs/jupiter/home.