Are there any Virtuoso plans for Cloud technologies (Openstack, etc..)?
It is part of the LOD2 OpenStack deliverables, but this is the Open Source Edition only (i.e., no
replication, clustering, fine-grained ACL based security, and virtual dbms functionality for making RDF
views over SQL data sources). You can also instantiate Virtuoso instances using the Amazon AWS Cloud etc.
Do I have to stop the cluster to add a node or partitioning an index?
Not if you enable the "elastic cluster" option from the get-go.
How do I attach the Virtuoso Virtual Database Engine to ODBC- or JDBC-accessible Data Sources?
See OpenLink HOWTO guides that showcase how to connect Virtuoso's Virtual Database Engine
to local or remote data sources including Firebird, DB2, Informix, Ingres, MySQL, Microsoft SQL Server,
Oracle, PostgreSQL, Progress, Sybase, and others accessible by ODBC or JDBC.
How do I create RDF-based Linked Data Views over Relational Data Sources?
This page discusses the basics of creating RDF-based Linked Data Views over Relational Data Sources,
and links to several other pages with specific guides for various local and remote (ODBC- and JDBC-
accessible) data sources.
How do I explore Linked Data using the Microsoft Pivot Viewer?
See OpenLink HOWTO guide that showcases how to use a Virtuoso hosted instance
of the Microsoft PivotViewer as a Linked Data front-end for follow-your-nose data exploration.
How do I explore Linked Data using the HTML5-based Pivot Viewer?
See OpenLink HOWTO guide that showcases how to use a Virtuoso
hosted instance of the Microsoft PivotViewer as a Linked Data front-end for
follow-your-nose data exploration.
How do I install and configure the Virtuoso Faceted Browser?
See required prerequisites, pre-installation steps, VAD package
installation, post-installation steps, and example tutorials.
How do I use R2RML to map RDB to RDF with Virtuoso?
R2RML, a W3C Recommendation, is a language for expressing customized mappings from relational
databases to RDF data sets. Such mappings provide the ability to view existing relational data
in the RDF data model, expressed in a structure and target vocabulary of the mapping author's
choice. R2RML mappings are themselves RDF graphs written in Turtle syntax. R2RML is becoming
the generic standard adopted by most vendors of tools mapping relational data to RDF, enabling
the interoperability of R2RML scripts, whether created with such tools or by hand. This page
discusses how to use R2RML specifically with Virtuoso.
How do I use SPARQL to dynamically generate CXML collections for the Microsoft or HTML5-based PivotViewer?
See OpenLink HOWTO guide that showcases the generation of CXML based output from SPARQL queries. This output is then used as input for the Microsoft or HTML5-based PivotViewer.
How do I use Virtuoso to deploy Linked Data to the Web?
This page discusses some of the difficulties faced in exposing RDF data and in bridging
the "Linked Data Web" and the traditional "Document Web". Two generic approaches to
resolving these deployment challenges are described, content negotiation and URL rewriting,
before looking at OpenLink Virtuoso, both from the standpoint of how it implements these
solutions and how Linked Data is deployed.
How do I use just one click on Virtuoso's HTML-based Wizard to
Generate and Deploy RDF-based Linked Data from Relational Databases?
See example of One-Click Linked Data Generation & Deployment of Linked
Data Views over Relational Data Sources with Virtuoso.
Is Virtuoso currently evaluating NoSQL database for the storage of quads?
Virtuoso is a Native Hybrid DBMS (it is SQL and NoSQL combined).
What are the best options to offer High-Avaliability and Disaster Recovery?
Is it possible to move data from one datacenter to another and how is data transferred?Are there any
numbers about the speed of data replication between two datacenters and consistency of the process?
You can use replication for HA across Clusters or Single-Server instances. We have transactional
replication (nearly instantaneous) and its used by some of our large customers e.g., Globo of Brazil which
used this Virtuoso setup for the entire World Cup 2014 without any issues.
What is the Virtuoso strategy to scale and how is it possible to start small and then add servers if needed?
Yes, you start with single-server, enable elastic cluster option, and then add nodes as scalability demands increase.
What is the current status of development for Virtuoso federation of triple stores?
We support SPARQL-FED, federated SPARQL has been a Virtuoso feature since the start of time.
What is the differences in terms of performance/scalability between 2 cluster configurations?
1st configuration: 4 cluster nodes, 3 instances per cluster node (quorum), 1 instance
per cluster host node, 12 cluster host nodes; 2nd configuration: 4 cluster nodes, 3
instances per cluster node (quorum), 4 instances per cluster host node, 12 cluster host nodes: -- This is more
to do with how many Virtuoso Server processes are running per cluster node. You will have more OS resources
available as the Virtuoso instances are reduced. Ideally, you want to spread the instances over distinct
machines so that you have resources pooled across those machines. One instance per cluster node will work better
than Four instances per cluster node.
When Virtuoso federation of triple stores will be available and how does it compare to clustering?
We already have this. In regards to Clustering that is more to do with horizontal partitioning of the
database across many machines (or virtual machines) combined with parallel execution of queries etc.
You can use SPARQL-FED with a Virtuoso Cluster, just as you would a single-server setup.