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Chapter 7 HPSS User Interface Configuration
HPSS Installation Guide September 2002 445
Release 4.5, Revision 2
For Linux systems, it is assumed that the system on which XFS is running has been configured with
the appropriate kernel and XFS versions as given in Section 2.3.5.1: HPSS/XFS HDM Machine on
page 52.
For DFS HDMs, two additional steps must be performed before continuing to the configuration of
the HDM:
1. Configure DFS SMT Kernel Extensions (AIX)
2. Configure DCE DFS
The following sections describe these extra steps in more detail. For XFS HDMs, skip ahead to
Section 7.6.3.3: Configuring an HDM Server (DFS & XFS) on page 448.
7.6.3.1 Configuring DFS SMT Kernel Extensions on AIX (DFS Only)
The DFS SMT kernel extension software should be configured to use the shortest possible timeout
parameter for delay. This parameter determines the interval at which the kernel backs off when
HDM response is slow, which can happen if a file is being staged to Episode from HPSS and the
data is not yet available on Episode. The timeout parameter is set with -delay. The default value
should not be used, since it can cause the system to take up to 17 minutes to process a single end-
user request. It is recommended that delay be set to 1. The parameter is expressed as an exponent
that is applied to a base of 4 seconds. Hence, setting the parameter to 1 causes a 4 second delay.
Configuring this parameter is described in the next section.
7.6.3.2 Configuring DCE DFS (DFS Only)
To avoid data and name space inconsistencies, the HDM should be started before the aggregates it
manages are exported. The safest way to ensure this is to modify the startup scripts.
The first thing to do is to create the following new scripts:
/opt/dcelocal/tcl/user_cmd.tcl
/var/hpss/hdm/hdm1/pre_start_dfs
/var/hpss/hdm/hdm1/pre_stop_dfs
/var/hpss/hdm/hdm1/post_stop_dfs
The new scripts take care of loading the DFS SMT Kernel extensions and starting the HDM. For
purposes of discussion, the last three scripts are assumed to be in /var/hpss/hdm/hdm1; but any
suitable directory can be used as long as user_cmd.tcl has been set up to point to that directory.
The example scripts below assume that a site runs more than one HDM on a machine, and that
these HDMs obey certain conventions. The scripts will have to be modified if different conventions
are used, and can be simplified on machines that have only one HDM. The following convention
makes it particularly easy to write the scripts and to use hdm_admin to administer the resulting
system. In this convention, an HDM whose ServerID parameter is <N> works with data files in the
directory named /var/hpss/hdm/hdm<N> and uses a shared memory key given by 3788+<N>.
For more information on the ServerID and shared memory key concepts, refer to Section 7.6.3.3.
For more information on hdm_admin, refer to Section 6.6: Using hdm_admin (page 108) in the HPSS
Management Guide.