Monthly Archive for April, 2007

Subversion Comes of Age

Over the past few weeks I’ve had the great pleasure of meeting quite a few senior mangers and executives from some of the world’s largest companies to talk about source code management (SCM). The recurring theme from them all has been their readiness to adopt an open source product to manage their source code.

The product in question is Subversion.

Now that’s pretty cool, but now consider that most of these companies are ripping out proprietary technology in favor of Subversion and you have an industry trend that may already be upon us.

This isn’t new though – who would have thought that Linux would challenge Windows, JBoss would challenge BEA or even that MySQL would dare to take on Oracle. By the time the market realizes that open source is a legitimate challenger, it’s already happened. The result is nearly always a commodity market with terrific downward price pressures – good for customers, bad for vendors.

Subversion is showing those characteristics. Managers seem to understand that the SCM repository is commodity. They should not be paying millions of dollars in support and maintenance for that. Add administration costs to the equation, and proprietary SCM is an expensive proposition – even for companies with huge IT budgets.

So is cost the reason so many are looking to Subversion? Well, sure its free, but that’s not enough – CVS is free remember, and growth for that product has slowed dramatically. Subversion is really liked by the development community so there’s lots of innovation. Many of the annoying things with CVS such as a lack of atomic commits are fixed with Subversion. This makes Subversion a whole lot easier to adopt from a large enterprise perspective. What’s more, the Apache/BSD license is not as intrusive as GPL, particularly for vendors looking to OEM.

So the future is looking good for Subversion, which is great news for our company, WANdisco. In fact the timing could hardly be better. Many companies looking at Subversion usually have multiple sites so they go and look for a Subversion Multi-Site product. A cursory glance at Google will quickly get you to our active/active replication solution for Subversion. Disaster recovery is also a significant issue, and we can provide that on a WAN scale… more about that next time.


About David Richards

David is CEO, President and co-founder of WANdisco and has quickly established WANdisco as one of the world’s most promising technology companies. Since co-founding the company in Silicon Valley in 2005, David has led WANdisco on a course for rapid international expansion, opening offices in the UK, Japan and China. David spearheaded the acquisition of Altostor, which accelerated the development of WANdisco’s first products for the Big Data market. The majority of WANdisco’s core technology is now produced out of the company’s flourishing software development base in David’s hometown of Sheffield, England and in Belfast, Northern Ireland. David has become recognised as a champion of British technology and entrepreneurship. In 2012, he led WANdisco to a hugely successful listing on London Stock Exchange (WAND:LSE), raising over £24m to drive business growth. With over 15 years' executive experience in the software industry, David sits on a number of advisory and executive boards of Silicon Valley start-up ventures. A passionate advocate of entrepreneurship, he has established many successful start-up companies in Enterprise Software and is recognised as an industry leader in Enterprise Application Integration and its standards. David is a frequent commentator on a range of business and technology issues, appearing regularly on Bloomberg and CNBC. Profiles of David have appeared in a range of leading publications including the Financial Times, The Daily Telegraph and the Daily Mail. Specialties:IPO's, Startups, Entrepreneurship, CEO, Visionary, Investor, ceo, board member, advisor, venture capital, offshore development, financing, M&A

Keeping Multiple Subversion Repositories in Sync

With Subversion 1.4svnsync was introduced for this purpose. The key problem with using svnsync for multiple Subversion repositories distributed over the WAN is its reliance on a master-slave architecture. While svnsync does provide the advantage of having local read-only repositories at each of the remote development sites, only the master repository is writeable. The master repository is then replicated to the read only slaves. However, the replication process can place a significant load on the network and servers. Because of this, replication tends to happen on an infrequent basis, leaving the read-only slave repositories that remote sites do their checkouts from out of sync with the master much of the time. As a result, commit failures due to update conflicts on the master repository can become a problem. In order to avoid commit failures, developers at the slave repository sites have to do updates over the WAN against the master Subversion repository before doing their commits. This can negate most of the expected network performance and developer productivity benefits of using svnsync in a distributed development environment.

Other solutions such as svk do allow multiple repositories to be readable as well as writeable, but there are no guarantees of consistency across the repositories. A commit can succeed on a developer’s local repository where there are no conflicts, and fail when it’s copied to other sites’ repositories due to update conflicts. This can make administration extremely difficult.

WANdisco solves these problems by turning distributed Subversion repositories into peers. All of the repositories are writeable, and consistency across the repositories is guaranteed. WANdisco’s active-active replication capabilities allow developers to work at LAN speed over the WAN for both read and write operations, while keeping all of the repositories in sync, in effect in real-time. WANdisco also provides self-healing capabilities that automate disaster recovery after a network outage or server failure.


About Jim Campigli