Subversion MultiSite - Evaluation Guide

Table of Contents

  1. Introduction Video
  2. MultiSite Frequently Asked Questions
  3. Pre-installation Checklist
  4. Prepare the Evaluation Environment
  5. WANdisco Software Installation and Configuration (with video)
  6. Running the Evaluation

Introduction Video

Watch our 10-minute introductory video for a technical overview of Subversion MultiSite

Can't see the video? Open a new window to view it on YouTube

 
To contact us email sales [at] wandisco [dot] com, submit a product download request or request a quotation.

You'll need to provide us with the following information:

  • Number of Sites
  • Number of Subversion Users
   
  • Operating System and Version
  • Version of Subversion

Upon approval, WANdisco will send you a link to a trial version of Subversion MultiSite, along with a 15-day evaluation key.

MultiSite Frequently Asked Questions

Q. What happens if users at separate sites try to change the same file at the same time?

A. When a write operation is received by the replicator it must first reach an agreement based on a configurable quorum mechanism. Once this agreement is reached, each commit will be assigned a unique global sequence number (GSN) and the commit with the lower GSN wins. The clients will experience exactly the same behavior as if they had performed a simultaneous commit against a stand-alone subversion server. The client whose commit has the lowest GSN is submitted to Subversion first and Subversion will respond to that client with a commit succeeded message. The client whose commit has the higher GSN comes in second, and Subversion will respond with the standard "out of date" error. This functionality improves collaboration among users who are globally distributed by allowing them to resolve conflicts as they occur in real-time.

Q. What about the response time for users? It sounds like they will have to wait for updates across multiple sites?

A. The updates will arrive at the remote sites in the same amount of time it would take for a remote client to checkout the file for the first time. The significant difference is, once the file is there, all the remaining clients will have LAN speed access to the file. Imagine how much bandwidth is being consumed by All the remote clients downloading the same files over and over again. And remember that with a singleton quorum, users at the DN will experience LAN-speed performance for read and write transactions since their commits can be processed immediately.

Q. What happens if the network goes down between sites or a server at one site becomes unavailable?

A. When the nodes in a replication group are not all able to communicate, some will remain writable and some will be read-only. When the network is restored, the read-only nodes will catch up with any transactions they missed automatically without any manual intervention.

For more frequently asked questions see the complete list in our knowledgebase article.

Pre-installation Checklist

The better understanding you have of the installation requirements, the smoother your deployment will go.
You should start by reading through the Pre-installation Checklist

Ensure that you have the following components available on each server:

  • Matching Operating System and version
  • Matching versions of Subversion, version 1.4 or later
   
  • Matching versions of Apache, version 2.2.3 or later.
  • Matching versions of the JDK 1.6, and Perl (5.6.1 or later)

For a fully tested version of Subversion based on the most recent, stable release, including the latest fixes,
we recommend our Certified Subversion Binaries.

Prepare the Evaluation Environment

Prepare your evaluation environment with 2 servers, set up as specified in the pre-installation checklist in the previous step.

You will also need to configure fully synchronized copies (same revision level) of a test repository on each server. Configure Apache identically on both servers with the appropriate user authentication mechanisms in place.

Read our article on setting up Subversion authentication with LDAP or Active Directory.

WANdisco Software Installation and Configuration

Can't see the video? Open a new window to view it on YouTube

You can follow the installation using the Installation Guide for Subversion MultiSite 4.0

Running the Evaluation

At this point you should have two servers configured with synchronized repositories and WANdisco replication enabled. Run a series of tests with Subversion checkouts and commits to verify the Subversion performance and stability of the system in a replicated environment.

You should produce and follow a test plan to ensure that your evaluation matches your own requirements for WANdisco.
A sample test plan can be found here.

Buy It!

Finish where you started by contacting WANdisco sales and thank you for evaluating Subversion MultiSite.

WANdisco offers a full range of Subversion training, consulting, migration, and implementation services.