IBM Hub/Switch Installation Manual

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

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Chapter 7 HPSS User Interface ConfigurationHPSS Installation Guide September 2002 417Release 4.5, Revision 2The HPSS_HOSTNAME environment variable is used to specify the hostname to be used forTCP/IP listen ports created by the Client API. The default value is the default hostname of themachine on which the Client API is running. This value can have a significant impact on datatransfer performance for data transfers that are handled by the Client API (i.e., those that use thehpss_Read and hpss_Write interfaces).The HPSS_TCP_WRITESIZE environment variable is used to specify the amount of data to bewritten 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 improvedthroughput. This environment variable may not affect the actual value used, based on the contentsof 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 transportmechanism to be used for data transfers handled by the Client API. The only valid value is TCP forTCP/IP transfers. The default value is TCP.The HPSS_PRINCIPAL environment variable is used to specify the DCE principal to be used wheninitializing 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 inHPSS log messages if the logging feature of the Client API is enabled. The default value is “ClientApplication”.The Client API, if compiled with debugging enabled, uses two environment variables to controlprinting 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. Twospecial cases for the debug path exist: stdout and stderr, which will use the standard output orstandard error I/O streams, respectively.The HPSS_NUMRETRIES environment variable is used to control the number of retries to attemptwhen an operation fails. Currently this class of operation includes library initialization andcommunications 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 4The HPSS_BUSY_RETRIES environment variable is used to control the number of retries to beperformed when a request fails because the Bitfile Server does not currently have an availablethread to handle that request. A value of zero indicates that no retries are to be performed, and avalue of “-1” indicates that retries should be attempted until either the request succeeds or fails foranother reason. The default value is 3.The HPSS_BUSY_DELAY environment variable is used to control the number of seconds to delaybetween retry attempts. Note that this value is used both for retrying initialization operations (seeHPSS_NUMRETRIES) and Bitfile Server requests (See HPSS_BUSY_RETRIES). The defaultvalue is 15.The HPSS_RETRY_STAGE_INP environment variables is used to control whether retries areattempted on attempts to open files in a Class of Service that is configured for background stagingon open. A non-zero value indicates that opens which would return -EINPROGRESS to indicatethat the file is being staged will be retried (using the same control mechanisms described in theprevious paragraph), while a value of zero indicates that the -EINPROGRESS return code will bereturned to the client. The default value is non-zero.