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Toolset Components:
 

ARCHER Data Services

Overview

The ARCHER Data Services (ADS) infrastructure supports other components in the ARCHER Toolset, and incorporates both third-party and ARCHER-developed software. It provides data storage via SRB, metadata storage with ICAT, and authentication through MyProxy.

 

ADS is made up of two layers:

  • ADS Service Layer provides web service interfaces to the data and metadata storage.
  • ADS Infrastructure Layer provides distributed storage, authentication, and an optional certificate authority.

Infrastructure Layer

The ADS Infrastructure Layer is a streamlined package of third party grid components such as Globus, MyProxy and SRB with customisations to allow authentication to an LDAP server. The components are all installed through automated deployment scripts with minimal configuration required.

 

SRB, or Storage Resource Broker, is a layer of infrastructure that provides a secure grid file storage system. It is a commercial product, free for use by academic institutions, and with full source code available. One or more network file systems normally provide the data storage.

 

VDT is a grid software packaging system that installs several grid components, including MyProxy and the Globus libraries.

 

MyProxy is a service that listens on port 7512, generating short-lived certificates called “proxies” for users upon request. It serves these over the network, allowing users access to remote services. ARCHER adds LDAP authentication to the standard MyProxy installation.

 

Many parts of ARCHER Toolset require a common Certificate Authority (CA) to sign certificates. ARCHER Data Services can set up MyProxy to function as a CA. This is useful in a testing or development environment.

Service Layer

The ADS Service Layer is composed of two web applications, ICAT and MCAText.

 

ICAT is a metadata storage service that implements the CCLRC Scientific Metadata Model version 2 to record information about scientific experiments. The data from the experiments itself is stored on the SRB, while the metadata is held in the ICAT. The ICAT’s storage is implemented as a PostgreSQL database, which is installed through the Archer XDMS application.

 

MCAText is an ARCHER-developed web service layer over SRB and its MCAT database. It provides a high performance mechanism for other services to lookup authorisation information on content within SRB. It provides update notification to other services when content is modified, moved, or created. It is used by certain ARCHER tools, including the ICAT service and ARCHER Collaborative Workspace.

Configuration

The System Administrator Guides discuss several configurations. However, the standard, tested ARCHER configuration is as follows:

 

Downloads

Source code, and deployment scripts, for all components can be downloaded on the
Downloads page.
 
Downloads