IBM Hub/Switch Installation Manual

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

Contents

Chapter 2 HPSS Planning54 September 2002 HPSS Installation GuideRelease 4.5, Revision 2transfer method, which provides for intra-machine transfers between either Movers or Movers andHPSS clients directly via a shared memory segment.Along with shared memory, HPSS also supports a Local File Transfer data path, for client transfersthat involve HPSS Movers that have access to the client's file system. In this case, the HPSS Movercan 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 acombination of TCP/IP and User Datagram Protocol (UDP)/IP (i.e., one of the two protocols orboth of the protocols). However, during the development and testing of HPSS, it was discoveredthat using TCP/IP would result in increasing and unbounded memory utilization in the serversover time (which would eventually cause servers to terminate when system memory and pagingspace resources were exhausted). Because of this behavior when using TCP/IP for the DCE RPCmechanism, the HPSS servers should only utilize UDP/IP for control communications. The defaultHPSS installation/configuration process will enable only UDP/IP for DCE RPC communicationswith the HPSS servers. See Section 5.3: Define the HPSS Environment Variables (page 216) for furtherdetails (specifically the environment variable RPC_SUPPORTED_PROTSEQS).The DCE RPC mechanism, by default, will use all available network interfaces on nodes that havemultiple networks attached. In cases where one or more nodes in the DCE cell is attached tomultiple networks, it is required that each node in the DCE cell be able to resolve any other networkaddress via the local IP network routing table. The environment variableRPC_UNSUPPORTED_NETIFS may be used to direct DCE to ignore certain network interfaces,especially if those interfaces are not accessible from other nodes in the cell. For example, to instructDCE to ignore a local HiPPI interface as well as a second ethernet interface,RPC_UNSUPPORTED_NETIFS could be set to “hp0:en1”. Note that this must be done prior toconfiguring DCE. 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 RobotsAll HPSS PVRs are capable of sharing a robot with other tape management systems but care mustbe taken when allocating drives among multiple robot users. If it is necessary to share a drivebetween HPSS and another tape management system, the drive can be configured in the HPSS PVRbut left in the LOCKED state until it is needed. When needed by HPSS, the drive should be set toUNLOCKED by the HPSS PVR and should not be used by any other tape management systemwhile in this state. This is critical because HPSS periodically polls all of its unlocked drives even ifthey are not currently mounted or in use.When using RAIT PVRs, an extra level of complexity is added by the virtualization of the physicaldrives into logical drives. Locking a given logical drive in HPSS would not necessarily guaranteethat HPSS will not access it via another logical drive. It is therefore not recommended to shareddrives managed by a RAIT PVR.The STK RAIT PVR cannot be supported at this time since STK has not yet made RAITgenerally available.Generally, only one HPSS PVR is required per robot. However, it is possible for multiple PVRs tomanage a single robot in order to provide drive and tape pools within a robot. The drives in therobot must be partitioned among the PVRs and no drive should be configured in more than one