IBM Hub/Switch Installation Manual page 417

The HPSS_HOSTNAME environment variable is used to specify the hostname to be used for
TCP/IP listen ports created by the Client API. The default value is the default hostname of the
machine on which the Client API is running. This value can have a significant impact on data
transfer performance for data transfers that are handled by the Client API (i.e., those that use the
hpss_Read and hpss_Write interfaces).
The HPSS_TCP_WRITESIZE environment variable is used to specify the amount of data to be
written with each individual request to write data to a network connection during a data transfer.
For some networks, writing less than the entire size of the client buffer has resulted in improved
throughput. This environment variable may not affect the actual value used, based on the contents
of the HPSS network options file - see Section 6.10.2 for further details.
The HPSS_TRANSFER_TYPE environment variable is used to specify the data transport
mechanism to be used for data transfers handled by the Client API. The only valid value is TCP for
TCP/IP transfers. The default value is TCP.
The HPSS_PRINCIPAL environment variable is used to specify the DCE principal to be used when
initializing the HPSS security services. The default value is hpss_client_api.
The HPSS_DESC_NAME environment variable is used to control the descriptive name used in
HPSS log messages if the logging feature of the Client API is enabled. The default value is "Client
Application".
The Client API, if compiled with debugging enabled, uses two environment variables to control
printing debug information. HPSS_DEBUG, if set to a non-zero value, will enable debug messages.
By default, these messages will go to the standard output stream. If HPSS_DEBUGPATH is set,
however, these messages will be directed to the file indicated by this environment variable. Two
special cases for the debug path exist: stdout and stderr, which will use the standard output or
standard error I/O streams, respectively.
The HPSS_NUMRETRIES environment variable is used to control the number of retries to attempt
when an operation fails. Currently this class of operation includes library initialization and
communications failures. A value of zero indicates that no retries are to be performed, and value of
"-1" indicates that the operation will be retried until successful. The default value is 4
The HPSS_BUSY_RETRIES environment variable is used to control the number of retries to be
performed when a request fails because the Bitfile Server does not currently have an available
thread to handle that request. A value of zero indicates that no retries are to be performed, and a
value of "-1" indicates that retries should be attempted until either the request succeeds or fails for
another reason. The default value is 3.
The HPSS_BUSY_DELAY environment variable is used to control the number of seconds to delay
between retry attempts. Note that this value is used both for retrying initialization operations (see
HPSS_NUMRETRIES) and Bitfile Server requests (See HPSS_BUSY_RETRIES). The default
value is 15.
The HPSS_RETRY_STAGE_INP environment variables is used to control whether retries are
attempted on attempts to open files in a Class of Service that is configured for background staging
on open. A non-zero value indicates that opens which would return -EINPROGRESS to indicate
that the file is being staged will be retried (using the same control mechanisms described in the
previous paragraph), while a value of zero indicates that the -EINPROGRESS return code will be
returned to the client. The default value is non-zero.
HPSS Installation Guide
Release 4.5, Revision 2
Chapter 7
September 2002
HPSS User Interface Configuration
417