Chapter 2 HPSS PlanningHPSS Installation Guide September 2002 77Release 4.5, Revision 2• Mover to Mover data transfers (accomplished for migration, staging, and repackoperations) also will impact the planned Mover configuration. For devices that supportstorage classes for which there will be internal HPSS data transfers, the Movers controllingthose devices should be configured such that there is an efficient data path among them. IfMovers involved in a data transfer are configured on the same node, the transfer will occurvia a shared memory segment (involving no explicit data movement from one Mover to theother).2.6.11 Logging ServiceLogging Services is comprised of the Log Daemon, Log Client, and Delog processes.If central logging is enabled (default), log messages from all HPSS servers will be written by theLog Daemon to a common log file. There is a single Log Daemon process. It is recommended thatthe Log Daemon execute on the same node as the Storage System Manager, so that any Delogsexecuted by the Storage System Manager can access the central log file. If the central log file isaccessible from other nodes (e.g., by NFS), it is not required that the Log Daemon execute on thesame node as the Storage System Manager.The Delog process is executed as an on-demand process by the Storage System Manger, or can beexecuted as a command line utility. If Delog is to be initiated from the Storage System Manager, theDelog process will execute on the same node as the Storage System Manager. If Delog is initiatedfrom the command line utility, the central log file must be accessible from the node on which thecommand is being executed (e.g., NFS mounted). Refer to Section 1.16.2: Viewing the HPSS LogMessages and Notifications (page 37) in the HPSS Management Guide for detailed information onDelog.If a Mover is being run in the non-DCE mode (where the processes that perform the devicemanagement and data transfers run on a different node from the processes that handle theconfiguration and managements interfaces), all Mover logging services will be directed to the LogClient running on the node on which the Mover DCE/Encina process runs.2.6.12 Metadata MonitorThe primary function of the Metadata Monitor is to periodically collect statistics on the amount ofspace used by SFS and notify SSM whenever the percentage of space used exceeds variousthresholds.A single Metadata Monitor server monitors one and only one Encina SFS server. If multiple EncinaSFS servers are used in an HPSS configuration, multiple Metadata Monitor servers should also bedefined (one per Encina SFS server). A Metadata Monitor server does not necessarily have toexecute on the same machine as the Encina SFS server it monitors.2.6.13 NFS DaemonsBy default files and directories created with NFS will have their HPSS account index set to the user'sdefault account index. Account validation is recommended with NFS if consistency of accountinginformation is desired. If account validation is not enabled, it may not be possible to keepaccounting information consistent. For example, if users have no DCE account, their UID will beused as the account. This may conflict with users set up to use site style accounting in the same cell.
