Chapter 2 HPSS Planning
54 September 2002 HPSS Installation Guide
Release 4.5, Revision 2
transfermethod, which provides for intra-machine transfers between either Movers or Movers and
HPSS clients directly via a shared memory segment.
Alongwith shared memory, HPSS also supports a Local File Transferdata path, for client transfers
thatinvolve HPSS Movers that have access to the client's file system. In this case, the HPSS Mover
can be configured to transfer the data directly to or from the client’s file.
The DCE RPC mechanism used for HPSS control communications can be configured to utilize a
combination of TCP/IP and User Datagram Protocol (UDP)/IP (i.e., one of the two protocols or
both of the protocols). However, during the development and testing of HPSS, it was discovered
that using TCP/IP would result in increasing and unbounded memory utilization in the servers
over time (which would eventually cause servers to terminate when system memory and paging
space resources were exhausted). Because of this behavior when using TCP/IP for the DCE RPC
mechanism,the HPSS servers should only utilize UDP/IP for control communications. The default
HPSS installation/configuration process will enable only UDP/IP for DCE RPC communications
withthe HPSS servers. See Section 5.3: Definethe HPSS Environment Variables (page 216) for further
details (specifically the environment variableRPC_SUPPORTED_PROTSEQS).
TheDCE RPC mechanism, by default, will use all available network interfaces on nodes that have
multiple networks attached. In cases where one or more nodes in the DCE cell is attached to
multiplenetworks, it is required that each node in the DCE cell be able to resolve any other network
address via the local IP network routing table. The environment variable
RPC_UNSUPPORTED_NETIFS may be used to direct DCE to ignore certain network interfaces,
especiallyif those interfaces are not accessible from other nodes in the cell. For example, to instruct
DCE to ignore a local HiPPI interface as well as a second ethernet interface,
RPC_UNSUPPORTED_NETIFScould be set to “hp0:en1”. Note that this must be done prior to
configuringDCE. If used, this environment variable should be set system wide by placing it in the
/etc/environment file for AIX or in the/etc/default/init file for Solaris.
2.4.2 Tape Robots
AllHPSS PVRs are capable of sharing a robot with other tape management systems but care must
be taken when allocating drives among multiple robot users. If it is necessary to share a drive
betweenHPSS and another tape management system, the drive can be configured in the HPSS PVR
but left in the LOCKED state until it is needed. When needed by HPSS, the drive should be set to
UNLOCKED by the HPSS PVR and should not be used by any other tape management system
whilein this state. This is critical because HPSS periodically polls all of its unlocked drives even if
they are not currently mounted or in use.
Whenusing RAIT PVRs, an extra level of complexity is added by the virtualization of the physical
drives into logical drives. Locking a given logical drive in HPSS would not necessarily guarantee
that HPSS will not access it via another logical drive. It is therefore not recommended to shared
drives managed by a RAIT PVR.
The STK RAIT PVR cannot be supported at this time since STK has not yet made RAIT
generally available.
Generally, only one HPSS PVR is required per robot. However, it is possible for multiple PVRs to
manage a single robot in order to provide drive and tape pools within a robot. The drives in the
robot must be partitioned among the PVRs and no drive should be configured in more than one