Hub/Switch Installation Guide

Chapter 2 HPSS Planning

HPSS Installation Guide September 2002 91

Release 4.5, Revision 2

Site "Stat" Interface will be called (gk_site_CreateStats, gk_site_OpenStats, gk_site_StageStats)

and the Site Interface will not be permitted to return any errors on these requests. Otherwise, if

AuthorizedCaller is set to FALSE, then the normal Site Interface will be called (gk_site_Create,

gk_site_Open, gk_site_Stage)andtheSite Interfacewill beallowed toreturnnoerror or returnan

error to either retry the request later or deny the request. When the request is being completed or

aborted the appropriate Site Interface will be called (gk_site_Close, gk_site_CreateComplete,

gk_site_StageComplete).Examplesof when arequestgetsaborted arewhen theBFSgoesDOWN

or when the user application is aborted.

NOTES:

1. All open requests to the BFS will call the Gatekeeping Service open API (gk_Open). This

includes opens that end up invoking a stage.

2. Any stage call that is invoked on behalf of open will NOT call the Gatekeeping Service

stage API (gk_Stage). (e.g. The ftp site stage <ﬁlename> command will use the Gate-

keeping Service open API, gk_Open, rather than the Gatekeeping Service stage API,

gk_Stage.)

3. Direct calls to stage (hpss_Stage, hpss_StageCallBack) will call the Gatekeeping Service

stage API (gk_Stage).

4. If the site is monitoring Authorized Caller requests then the site policy interface won't be

allowedtodenyordelaytheserequests,howeveritwillstillbeallowedtomonitor these

requests. For example, if a site is monitoring Authorized Caller and Open requests, then

the site gk_site_Open interface will be called for open requests from users and the

gk_site_OpenStats interface will be called for open requests due an authorized caller

request (e.g. migration by the MPS). The site policy can NOT return an error for the open

due to migration, however it can keep track of the count of opens by authorized callers to

possibly be used in determining policy for open requests by regular users. Authorized

Caller requests are determined by the BFS and are requests for special services for MPS,

DFS, andNFS. These servicesrely ontimely responses,thus gatekeeping isnot allowed to

deny or delay these special types of requests.

5. The Client API uses the environment variable HPSS_GKTOTAL_DELAY to place a

maximumlimitonthenumberofsecondsacallwilldelaybecauseofHPSS_ERETRYstatus

codes returned from the Gatekeeper. See Section 7.1: Client API Conﬁguration on page 413

for more information.

Refer to HPSS Programmer's Reference, Volume 1 for further speciﬁcations and guidelines on

implementing the Site Interfaces.

2.9 Storage Characteristics Considerations

This section deﬁnes key concepts of HPSS storage and the impact the concepts have on HPSS

conﬁguration and operation. These concepts, in addition to the policies described above, have a

signiﬁcant impact on the usability of HPSS.

BeforeanHPSS systemcan beused, theadministrator hasto createadescription ofhow thesystem

istobe viewedby theHPSSsoftware. Thisprocessconsistsof learningas muchaboutthe intended

and desired usage of the system as possible from the HPSS users and then using this information