The following shows the syntax and entries expected of a configuration file for xdrive:
#
# This file MUST be named 'xdrive.toml'
# What follows are configurations for xdrive.
#
[xdrive]
#
# Specify the working directory. Xdrive will cd into
# this directory at the target machine.
# Logs will be written to ${dir}/log/.
#
dir = "the-home-dir-on-target-machine"
#
# Specify the target machines and the port Xdrive will
# use for communication. For each entry, an Xdrive instance
# will be started.
#
port = 7171
host = [ "host1", "host2", ...]
#
# Each [[xdrive.mount]] specifies a mountpoint.
# There can be multiple [[xdrive.mount]].
#
[[xdrive.mount]]
name = "name-of-a-mountpoint, e.g. mydata"
argv = ["plugin-fname-or-fpath", "argv1", "argv2", ...]
env = ["envname=envvalue", ... ]
The dir configuration value specifies the “home” directory of the
Xdrive program on each host. If the directory does not exist, it will
be created automatically.
The port configuration value gives the port number for the Xdrive TCP endpoint.
The host configuration value specifies an array of machines that Xdrive should run on.
One commonly used host configuration in Deepgreen DB is to have an
entry for each node of the cluster. Suppose you have a 2-node setup
where the hosts are mdw, sdw1-1, sdw1-2, sdw2-1, sdw2-2, you
would set up the host configuration like this:
# Run an xdrive on each of my segment machines.
host = [ "sdw1-1", "sdw2-1", ]
A setup like this lets
you use localhost in the external table DDL.
Utilizing the same concept as mounting a file system in UNIX, a mountpoint is a symbol that represents the root of a file system in Xdrive.
Multiple mountpoints may be specified in the configuration with the
[[xdrive.mount]] tag. Each mountpoint has:
name – a unique identifier to be used in the LOCATION clause for
invocation of the plugin,
argv – an array that spells out the command line arguments used
to invoke the plugin, and
env – an array that can be used to set up environment variables
for use by the plugin.
Next, let’s take a look the Deployment of Xdrive.