Hub/Switch Installation Guide

Chapter 7 HPSS User Interface Configuration
HPSS Installation Guide September 2002 431
Release 4.5, Revision 2
7.4 NFS Daemon Configuration
Before the HPSS NFS daemon can be started, any existing AIX or Solaris native NFS daemons
must be stopped and prevented from restarting. This is important because the NFS protocol does
not provide a way for clients to specify which of two daemons is wanted. When the system is set
up correctly, there should be no 'nfsd' or 'mountd' processes running. If nfsd was running
before,it maybenecessary tofreeup theportsit allocatedby usingthe'rpcinfo -d' command.Otherwisethe
HPSSdaemonmay notstartcorrectly.Also besure tostop rpc.lockdandrpc.stad.The HPSSNFSdaemon
does not support file locking.
Additional HPSS NFS configuration information is specified through the HPSS exports file and
through environment variables. If the default server name for the HPSS LS is not used, the
environment 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 variable
HPSS_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 as
expected aftera junction traversal (i.e.“cd ..”). Bydefault, NFS junction traversalis disabled. To
enable it, add HPSS_NFS_ENABLE_JUNCTIONS = “on” to the hpss_env file before bringing up
theStartupDaemon.Thisenvironmentsettingwillalsoallowjunctionstobemounted(i.e.“mount
hostname:/junction”).
HPSS NFS does not support yellow pages (Sun MicroSystems’ Network Information Services) to
validate hosts. HPSS NFS does provide an option to validate the network address of hosts
attemptingto mountHPSSdirectories.The defaultconfiguration disablesthischeck. Toenablethis
check, define the variable HPSS_MOUNTD_IPCHECK in the hpss_env file.
Note: For users who have several NFS clients concurrently updating and reading the HPSS
namespace anddepend onhaving their namespace changes immediatelyreflected in all clients,it
is necessary to perform NFS mounts with the noac option. Here is an example:
mount -orw,intr,timeo=30,noac hpssserver:/hpss /hpss
Usingthenoacoptionwilldegradeperformancesinceitprohibitscaching.OnlyuseitifNFSclients
rely on immediate HPSS namespace updates.
IfpeopleareusingNFStomountfilesystemsfromseveralhosts,asituationcandevelopwhereone
NFS daemon gets bogged down and then users can't access the other file systems either. This is a
commonproblemwithallNFSfilesystemsandisnotpeculiartoHPSS.HoweverbecausetheHPSS
NFS 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 NFS
mount points. All of the mount points for a particular NFS host should be kept in a directory
separate from the other hosts. (This is probably a good idea even if the clients are not mounting
HPSSfiles.)One convention fordoing thisis toname themount pointsbythe nameofthe hostthat
is 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 mount
points might be: /nfs/tardis/home, /nfs/tardis/public, and /nfs/jupiter/home
If these names aren't considered user friendly, the site can use symlinks to establish friendlier
names. For example, /hpss could point to /nfs/tardis, and /users could point to /nfs/jupiter/home.