Hub/Switch Installation Guide

Chapter 2 HPSS Planning

68 September 2002 HPSS Installation Guide

Release 4.5, Revision 2

MPS provides the capability of generating migration/purge report ﬁles that document the

activities of the server. The speciﬁcation of the UNIX report ﬁle name preﬁx in the MPS server

speciﬁc conﬁguration enables the server to create these report ﬁles. It is suggested that a complete

path be provided as part of this ﬁle name preﬁx. Once reporting is enabled, a new report ﬁle is

startedevery24 hours.Thenames ofthereportﬁlesaremadeup oftheUNIX ﬁlenamepreﬁxfrom

the server speciﬁc conﬁguration, plus a year-month-day sufﬁx. With reporting enabled, MPS will

generate ﬁle-level migration and purge report entries in real time. These report ﬁles can be

interpretedandviewed usingthe mps_reporterutility.Sincethenumberandsizeofthereportﬁles

growrapidly, each site shoulddevelop a cron jobthat will periodicallyremove the reportsthat are

no longer needed.

MPS uses threads to perform the migration and purge operations and to gather the storage class

statistics from the Storage Servers. In particular, MPS spawns one thread for each disk or tape

storage class on which migration is enabled and one thread for each disk storage class on which

purgeis enabled.Thesethreads arecreated at startup time andexist forthe lifeof theMPS.During

diskmigrationruns, MPSspawnsan additionalnumberof temporary threadsequal tothe product

of the number of copies being made (determined by the storage hierarchy conﬁguration) and the

numberofconcurrentthreadsrequestedformigration(conﬁguredintheRequestCountﬁeldinthe

migration policy). During tape migration runs, MPS spawns one temporary thread for each Tape

Storage Server within itsconﬁguredsubsystem. These threads exist only for the durationof a disk

or tape migration run. Purge does not use any temporary threads. MPS uses a single thread to

monitortheusagestatisticsofallofthestorageclasses.ThisthreadalsoexistsforthelifeoftheMPS.

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 storage

subsystem. MPS accomplishes this by polling the Storage Servers within its subsystem at the

interval speciﬁedintheMPS serverspeciﬁc conﬁguration.The resultingoutputisone linefor each

storage class for each storage subsystem in which that class is enabled. The MPS for a subsystem

does not report on classes which are not enabled within that subsystem. MPS also activates and

deactivates the warning and critical storage class thresholds.

Because the MPS uses the BFS and any Storage Servers within its assigned storage subsystem to

perform data movement between hierarchy levels, the BFS and the Storage Servers must be

runninginorderfortheMPStoperformitsfunctions.Inaddition,theMPSrequiresthattheStorage

Servers within its subsystem be running in order to report storage class usage statistics.

2.6.6 Gatekeeper

Each Gatekeeper may provide two main services:

1. Providing sites with the ability to schedule the use of HPSS resources using Gatekeeping

Services.

2. Providing sites with the ability to validate user accounts using the Account Validation

Service.

If the site doesn’t want either service, then it is not necessary to conﬁgure a Gatekeeper into the

HPSS system.

Sites can choose to conﬁgure zero (0) or more Gatekeepers per HPSS system. Gatekeepers are

associated with storage subsystems. Each storage subsystem can have zero or one Gatekeeper

associated with it and each Gatekeeper can support one or more storage subsystems. Gatekeepers