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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) and the Site Interface will be allowed to return no error or return an
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). Examples of when a request gets aborted are when the BFS goes DOWN
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
allowed to deny or delay these requests, however it will still be allowed to monitor 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, and NFS. These services rely on timely responses, thus gatekeeping is not allowed to
deny or delay these special types of requests.
5. The Client API uses the environment variable HPSS_GKTOTAL_DELAY to place a
maximum limit onthe number ofseconds a callwill delay because of HPSS_ERETRY status
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.
Before an HPSS system can be used, the administrator has to create a description of how the system
is to be viewed by the HPSS software. This process consists of learning as much about the intended
and desired usage of the system as possible from the HPSS users and then using this information