You control the execution mode by using environment variables or by specifying options in the PERFORMANCE statement in high-performance analytical procedures, or by a combination of these methods.
The important environment variables follow:
grid host identifies the domain name system (DNS) or IP address of the appliance node to which the SAS High-Performance Server Distributed Mode software connects to run in distributed mode.
installation location identifies the directory where the SAS High-Performance Server Distributed Mode software is installed on the appliance.
You can set an environment variable directly from the SAS program by using the OPTION SET= command. For example, the following statements define the grid host and the location where the SAS High-Performance software is installed on the appliance:
option set=GRIDHOST ="hpa.sas.com"; option set=GRIDINSTALLLOC="/opt/TKGrid";
Alternatively, you can set the parameters in the PERFORMANCE statement in high-performance analytical procedures. For example:
performance host ="hpa.sas.com"
install ="/opt/TKGrid";
A specification in the PERFORMANCE statement overrides a specification of an environment variable without resetting its value. An environment variable that you set in the SAS session by using an OPTION SET= command remains in effect until it is modified or until the SAS session terminates.
The key variable that determines whether a high-performance analytical procedure executes in single-machine or distributed mode is the grid host. The installation location is needed to ensure that a connection to the grid host can be made, given that a host is specified. This book assumes that the installation location has been set by your system administrator.
The following sets of SAS statements are functionally equivalent:
proc hpreduce; reduce unsupervised x:; performance host="hpa.sas.com"; run; option set=GRIDHOST="hpa.sas.com"; proc hpreduce; reduce unsupervised x:; run;