IBM Hub/Switch Installation Manual

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

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Chapter 2 HPSS Planning68 September 2002 HPSS Installation GuideRelease 4.5, Revision 2MPS provides the capability of generating migration/purge report files that document theactivities of the server. The specification of the UNIX report file name prefix in the MPS serverspecific configuration enables the server to create these report files. It is suggested that a completepath be provided as part of this file name prefix. Once reporting is enabled, a new report file isstarted every 24 hours. The names of the report files are made up of the UNIX file name prefix fromthe server specific configuration, plus a year-month-day suffix. With reporting enabled, MPS willgenerate file-level migration and purge report entries in real time. These report files can beinterpreted and viewed using the mps_reporter utility. Since the number and size of the report filesgrow rapidly, each site should develop a cron job that will periodically remove the reports that areno longer needed.MPS uses threads to perform the migration and purge operations and to gather the storage classstatistics from the Storage Servers. In particular, MPS spawns one thread for each disk or tapestorage class on which migration is enabled and one thread for each disk storage class on whichpurge is enabled. These threads are created at startup time and exist for the life of the MPS. Duringdisk migration runs, MPS spawns an additional number of temporary threads equal to the productof the number of copies being made (determined by the storage hierarchy configuration) and thenumber of concurrent threads requested for migration (configured in the Request Count field in themigration policy). During tape migration runs, MPS spawns one temporary thread for each TapeStorage Server within its configured subsystem. These threads exist only for the duration of a diskor tape migration run. Purge does not use any temporary threads. MPS uses a single thread tomonitor the usage statistics of all of the storage classes. This thread also exists for the life of the MPS.MPS provides the information displayed in the HPSS Active Storage Classes window in SSM.Each MPS contributes storage class usage information for the resources within its storagesubsystem. MPS accomplishes this by polling the Storage Servers within its subsystem at theinterval specified in the MPS server specific configuration. The resulting output is one line for eachstorage class for each storage subsystem in which that class is enabled. The MPS for a subsystemdoes not report on classes which are not enabled within that subsystem. MPS also activates anddeactivates the warning and critical storage class thresholds.Because the MPS uses the BFS and any Storage Servers within its assigned storage subsystem toperform data movement between hierarchy levels, the BFS and the Storage Servers must berunning in order for the MPS to perform its functions. In addition, the MPS requires that the StorageServers within its subsystem be running in order to report storage class usage statistics.2.6.6 GatekeeperEach Gatekeeper may provide two main services:1. Providing sites with the ability to schedule the use of HPSS resources using GatekeepingServices.2. Providing sites with the ability to validate user accounts using the Account ValidationService.If the site doesn’t want either service, then it is not necessary to configure a Gatekeeper into theHPSS system.Sites can choose to configure zero (0) or more Gatekeepers per HPSS system. Gatekeepers areassociated with storage subsystems. Each storage subsystem can have zero or one Gatekeeperassociated with it and each Gatekeeper can support one or more storage subsystems. Gatekeepers