Subversion Clustering

Subversion MultiSite Subversion Access Control

Overview
Features
Compare SVN Clustering to the Competition
What is Subversion?
Links and Resources

Enterprise Class Performance, Scalability, Availability and Backup for Subversion

Subversion Clustering eliminates the single point of failure and performance bottleneck of a central Subversion server over a local area network. By combining WANdisco's unique replication technology and intelligent load balancing software, Subversion can be deployed in an active-active cluster that delivers optimum performance, scalability and availability, with built-in continuous hot backup and automated recovery. Downtime and data loss are completely eliminated.

Where to Next:

Check out how Subversion Clustering stacks up against the competition, discover how to make Subversion agile, learn about Subversion Services, or get more information about pricing.

Features


	New in 4.0

	Watch the Webinar Replay SSL Support Encrypts all Network Traffic to Meet the Most Stringent Security Requirements Transactions between Subversion servers and between Subversion clients and servers can now be configured to use SSL. Parallel Transaction Processing Each repository now has its own transaction queue. This allows replicated transactions to be processed in parallel across multiple repositories for improved performance and tighter control in large development environments. Silent Installer Non-GUI installer automates deployment for faster implementation and minimal downtime when new servers are added to a Subversion Clustering implementation. Complete LDAP Integration for the Admin Console Multiple administrators can log on using their individual LDAP credentials. New RESTful API Allows third party monitoring systems and custom scripts to query Subversion Clustering's administration console and modify its configuration. Subversion Clustering operations can also be invoked externally through the API.

Features

Dynamically balances workload across Subversion servers at a single location over a LAN, or multiple locations thousands of miles apart with Subversion MultiSite (WAN Clustering).
Subversion LAN Clustering has no single point of failure. There is no sharing of disk, CPU or memory between servers in a cluster. Even load balancers can be paired for redundancy using the resilient cluster option.
Intelligent load balancing capabilities optimize performance for end users by taking each server’s current load into account before routing requests. Load balancing can also be configured to take the content of the data in a request into consideration so that specific tasks can be routed to the servers best suited to handle them.
The load balancers run as software services, not hardware appliances. This offers tremendous deployment flexibility and long-term scalability as a Subversion implementation grows.
There are no passive standby servers. All servers are active peers simultaneously supporting user requests.
All servers in a cluster are fully readable and writeable and always in sync, making the cluster appear to end users as a single, always available Subversion server.
When a network or server outage takes place, failover is transparent and immediate and recovery is automatic. Users experience no downtime or data loss, and the risk of human error is eliminated.
Automated failover and recovery capabilities can be used to take servers offline for maintenance without interrupting user access, making full 24-by-7 operation possible. When a server is brought back online after maintenance is complete, it resynchronizes automatically with the other servers in the cluster.
Connection draining allows existing tasks to be completed, while blocking new user connections before scheduled server maintenance takes place.
Hot deploy capability allows servers to be added to a cluster without any downtime.
Subversion LAN Clustering can be implemented stand-alone or in combination with Subversion MultiSite (WAN Clustering).

Can Subversion Clustering be Implemented With Just Two Nodes?

Subversion Clustering can be implemented with just two nodes. However, this will only support load balancing, not high availability. In a two node cluster, if one node fails, this leaves a single server and a single point of failure without another server to recover from. A minimum of three nodes is recommended to safely support both high availability and load balancing.

Subversion Clustering Optmizes Build Performance for Agile Development

Agile development is iterative and incremental, requiring continuous communication and continuous build integration. Subversion LAN Clustering allows build processes to be offloaded from the Subversion servers used by developers, significantly improving their productivity. At the same time, the latest changes from the development team are available on the other servers in the cluster where continuous builds are running.

A number of WANdisco's customers are implementing Subversion Clustering in combination with Subversion MultiSite (WAN Clustering) to fully enable agile development in a distributed environment. This combination eliminates WAN latency for remote developers as well as the performance bottleneck of a single Subversion server at the largest development sites.

Subversion Clustering vs. Shared Disk & Shared Memory Clustering:

Subversion Clustering's approach is truly shared-nothing. There is no sharing of disk, memory or CPU between servers in a cluster so there's no single point of failure or performance bottleneck. In addition, WANdisco's unique replication technology turns the servers in a cluster into mirrors of each other, achieving continuous hot backup by default.
Although the same write operations occur on every server in a cluster, near linear scaling is achieved. This is due to the fact that 80-90% of the operations against a Subversion server are typically read operations and Subversion Clustering distributes the load for read operations across all of the servers in a cluster. This has the effect of freeing up resources in each server to support write operations, so that write performance also improves.
Intelligent load balancing capabilities optimize performance for end users by taking each server's current load into account before routing requests, rather than relying on simplistic round-robin approaches. If one of the servers in the cluster goes down, users will automatically fail over to another available server. When a server is brought back online it recovers automatically from the other servers in the cluster.
Subversion Clustering's automatic recovery features also allow servers to be taken offline for maintenance without disrupting user access to the remaining servers. Many clustering solutions require all of the servers in a cluster to be brought down, just to take one server offline for maintenance, and recovery requires manual intervention.
WANdisco's transparent implementation approach means that Subversion's functionality doesn't change, so there's no user retraining.

What is Subversion?

Subversion is an open source version control system that stores and tracks changes made to any type of electronic data, including source code files, web pages, documents, or images. Subversion has experienced a phenomenal adoption rate because it offers features that make it easier to use and more cost-effective than competing commercial solutions, as well as its widely used open source predecessor, CVS. Forrester Research recently recognized Subversion as the sole leader in the Standalone Software Configuration Management (SSCM) category in a side-by-side comparison that included the most popular commercial SCM solutions.

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