Chapter 2 HPSS Planning
78 September 2002 HPSS Installation Guide
Release 4.5, Revision 2
Even if no client NFS access is required, the NFS interface may provide a useful mechanism for
HPSS name space object administration.
The HPSS NFS Daemon cannot be run on a processor that also runs the native operating system's
NFS daemon. Therefore it will not be possible to export both HPSS and native Unix file systems
fromthe same processor. In addition the NFS daemon will require memory and local disk storage
to maintain caches for HPSS file data and attributes. NFS memory and disk requirements are
discussed in Section 2.10.3.2 and 2.10.3.2.8. Since the NFS Daemon communicates with the HPSS
NameServer frequently, running the NFS Daemon on the same platform as the HPSS Name Server
is recommended.
NFS access to an exported subtree or fileset is controlled through the use of an exports file, which
is a Unix text file located on the machine where the HPSS NFS daemon is running. Entries in the
exports file tell which subtrees and filesets are exported and what client systems can access them.
Additional options are available to specify the type of access allowed and additional security
related features. Export entry options are described in more detail in Sections 2.8.4 and 7.4: NFS
Daemon Configuration (page 431).
Useof HPSS NFS also requires running an HPSS Mount Daemon component on the same platform
asthe HPSS NFS Daemon. As with standard UNIX NFS, the HPSS Mount Daemon provides client
systems with the initial handle to HPSS exported directories.
It is possible to run several NFS Daemons in HPSS, but there are some restrictions. The NFS
Daemonscannot run on the same platform, and the directory trees and filesets supported by each
daemon should not overlap. This is necessary because with overlapping directories, it is possible
for different users to be updating the same file at essentially the same time with unpredictable
results. This is typically called “the cache consistency problem.”
Bydefault, files created with NFS will have the HPSS accounting index set to -1, which means that
HPSS will choose the account code for the user. Standard HPSS accounting mechanisms are
supported only through the export file’sUIDMAP option, described in Section 7.4.1: The HPSS
Exports File on page 432. If theUIDMAP option is specified, the user ’s default account index will
be used for file creation. Thenfsmap utility provides a capability for specifying an account index
other than the user’s default.
2.6.14 Startup Daemon
The Startup Daemon is responsible for starting, monitoring, and stopping the HPSS servers.The
Daemon responds only to requests from the SSM System Manager. It shares responsibility with
each HPSS server for ensuring that only one copy of the server runs at a given time. It helps the
SSMdetermine whether servers are still running, and it allows the SSM to send signals to servers.
Normally, the SSM stops servers by communicating directly with them, but in special cases, the
SSM can instruct the Startup Daemon to send aSIGKILL signal to cause the server to shut down
immediately.
If a server is configured to be restarted automatically, the Startup Daemon will restart the server
when it is terminated abnormally. The server can be configured to be restarted forever, up to a
number of auto-restarts or no auto-restart.
Choose a descriptive name for the Daemon that includes the name of the computer where the
Daemonwill be running. For example, if the Daemon will be running on a computer named tardis,