Monthly Archive for June, 2013

WANdisco Announcements at Hadoop Summit 2013!

We’ve been busy at WANdisco and Hadoop Summit gave us the chance to share all of the product, partnership, and feature news we’ve been working on.

First and foremost, the release of Non-Stop NameNode WAN Edition marks the first and only Continous Availability™ solution for Hadoop clusters deployed over a WAN. With it, servers actively support clients at globally distributed locations and continuously synchronize with data nodes. The result is LAN-speed performance and access to the same data at every location with automatic failover and recovery both within and across data centers, enabling 100% uptime with unparalleled scalability and performance.

Non-Stop NameNode WAN Edition provides 100% Hadoop uptime over the WAN, automatic WAN backup and failover, complete WAN namenode sync, and more. For more information, visit the product page.

In addition to the launch of Non-Stop NameNode WAN Edition, WANdisco Distro (WDD) version 3.6 is now available, bringing a number of new features, fixes, and capabilities to our fully tested, certified and production-ready version of Apache Hadoop 2. WDD 3.6 includes S3-Enabled HDFS, which simplifies migration from Amazon’s public cloud without sacrificing support for third-party applications that use the S3 API.

Looking to the future, we’re proud to announce our collaboration with AMPlab of UC Berkeley in providing a technology preview of Spark and Shark. Spark offers significant new computation model capabilities and performance enhancements to deliver speeds up to 100 times faster than MapReduce on any Hadoop-supported filesystem. Shark addresses limitations of Apache Hive while natively supporting SQL and HQL as well as metastore, serialization formats, and user-defined functions. In addition to improving upon Hive, Shark allows users to cache data in-memory to vastly increase efficiency and provide maximum performance.

In partnership news, WANdisco announced another Non-Stop Alliance Partner, TCloud, to provide enterprises in Great China with comprehensive enterprise Hadoop deployment solutions. TCloud, a subsidiary of Trend Micro, has its headquarters in Beijing with additional satellite locations through Asia.

It is an exciting time for WANdisco and we are looking forward to bringing you more Big Data news.

WANdisco and Zaloni Announce Big Data Partnership

We’re pleased to announce we’ve partnered with Zaloni, a leading provider of agile Big Data and data management solutions, to enable enterprises to accelerate the adoption of Apache Hadoop and support Continuous Availability™ for their mission-critical applications.

Zaloni’s Bedrock Data Management Platform™ provides a unique foundation for Hadoop end-to-end design, build and deployment solutions. WANdisco provides Continuous Availability™ to data processed and stored in Hadoop. Together, we will provide enterprises with a full-lifecycle approach to Hadoop deployment, including use case discovery, development, integration, delivery and ongoing maintenance and support.

“We offer solutions that deliver 100% uptime for Hadoop, and our clients want to know that in addition to these products, they will be getting an effective implementation plan and support,” said David Richards, CEO of WANdisco. “The partnership with Zaloni will provide exactly that.”

WANdisco will be at Hadoop Summit June 26-27. Click here for 20% off registration.

Why Cassandra Lies to You

115px-Cassandra1Apache Cassandra is an open source, replicated store of key-value pairs (also commonly known as a NoSQL database) modeled after Amazon’s Dynamo.  Like Dynamo, Cassandra’s replication can be described as active-active, fault-tolerant, highly available and peer-to-peer.  Unlike WANdisco’s DConE replication technology, however, they do not guarantee consistency. Instead, they guarantee what they call “eventual consistency”.

“Eventual consistency” in this context means that Cassandra has to lie to you sometimes.

Let’s look at an example to illuminate this further.

Imagine an online merchant using Cassandra with a dozen worldwide replicas for inventory management. Our merchant’s supply of Widgets is down to the last one, and we start with all Cassandra replicas accurately reflecting this worldwide supply of one Widget.

Two customers, Michael and James, order a Widget at the nearly same time.  Both orders are fulfilled because the ordering software accesses two different replicas of Cassandra, each replica reporting one available Widget.  One replica has a record indicating that the last Widget was sold to Michael. The other has a conflicting record indicating that the last Widget was sold to James. Nobody is aware of this conflict.

Using the “gossip protocol”, the replicas now push records around until they are fully distributed.

Eventually, a replica sees both records, detects a conflict and moves to resolve the conflict.   A simplistic algorithm may resolve the conflict in favor of Michael, perhaps using timestamps and automatically generating an apology to James.  Over time, James’ order is rescinded in favor of Michael’s at all replicas, and other than the effect on customer relationship with a disappointed James, everything returns to normal.  Let’s just hope that in the midst of this process of conflict resolution and gossip protocol, the shipping department did not consult a replica with the wrong information and sent the last Widget to James!

Let’s now look at the same scenario using a true active-active technology with absolute consistency like WANdisco’s DConE replication.

As before, Michael and James try to buy a Widget.

Two replicas generate proposals.  One proposes that a Widget be sold to Michael. The other proposes that a Widget be sold to James. DConE delivers these proposals to the replicas, and they conclude Michael’s order was fulfilled and James’ was not.

Since all replicas have the same information, the replica accessed by Michael informs him that his order is fulfilled. The replica accessed by James informs him that Widgets are sold out. The replica accessed by Shipping indicates that the Widget should ship to Michael.

So while Cassandra may not want to lie to you, it can’t help it due to the effect of its eventual consistency.  DConE never lies, so when your data is really important to you, DConE’s absolute consistency is the ultimate in data-safe replication technology.

WANdisco and Dataguise Form Strategic Alliance

We’re pleased to announce another Non-Stop Alliance Partner: WANdisco and Dataguise have partnered to deliver a certified solution to protect data privacy and deliver risk assessment intelligence for enterprises using WANdisco Distro (WDD). With this announcement, DG for Hadoop™ is certified for WDD customers.

DG for Hadoop is a comprehensive, flexible and modular solution that delivers enterprise-class protection to sensitive data aggregated in Hadoop installations. Together, WANdisco and Dataguise will meet the standards that customers demand for their mission critical Hadoop environments.

“Data security is a critical requirement in today’s enterprise environment. Big Data brings new challenges to security and Dataguise meets those requirements and accelerates the adoption of Hadoop in these environments,” said David Richards, CEO of WANdisco. “Our mutual customers can look forward to meeting data protection challenges as well as overcoming global availability challenges with this partnership.”

Both companies will be at Hadoop Summit in San Jose, California next week. Click here for 20% off registration.

WANdisco Announces Partnership with Data Tactics

We’re proud to announce we’ve partnered with Data Tactics to deliver planning, implementation, and support services for Continuous Availability™ of Big Data deployments.

Data Tactics is focused on solving big data problems and has been building petascale enterprise systems leveraging Hadoop since 2008. Together, we will provide a comprehensive approach to Hadoop deployment, including business use case investigation, development, integration, delivery and ongoing services and support.

“Our clients need expert and effective implementation planning and support for our 100% uptime Hadoop solutions,” said David Richards, CEO of WANdisco. “Data Tactics has the insight, experience, and knowledge to deliver that.”

WANdisco will be at Hadoop Summit June 26-27. Click here for 20% off registration.


TortoiseSVN 1.8 is now available!

We’re very pleased to announce that TortoiseSVN 1.8 is now available to download. TortoiseSVN 1.8 is fully compatible with the newly-released Subversion 1.8.

This release of the popular Windows client for Apache Subversion contains a whole raft of changes designed to make your day to day development easier.

The changes include:

  • Coloring for TortoiseBlame

  • The ability to commit only parts of a file

  • An improvement to the Repository Browser to enable you to see all repositories by pointing at the root

  • Improvements to custom properties and client hook scripts

You can see a complete list of the changes here.

TortoiseSVN users are recommended to upgrade to this release as soon as possible.


WANdisco Announces Availability of Apache Subversion 1.8 binaries

Today sees the long-awaited release of Subversion 1.8, featuring significantly improved merge capabilities as promised at SVN Live last year, to address user needs.

With Subversion 1.8, users will benefit from merge functionality enhancements as well as major improvements in storage efficiency. The enhancements include:

  • Symmetric, or automatic, merge capability for simplifying the merge process and eliminating conflicts caused by users selecting the wrong type of merge.

  • Simultaneous change handling between branches rather than differentiating between sync and reintegration merge forms.

  • Rejection of merge attempts between unrelated branches to decrease the likelihood of user errors that often result in conflicts.

  • Decrease in server set-up costs.

  • Revision property packing and directory deltification to reduce backup and restore times as well as the number of files stored for up to more than 90% storage capacity savings.

You can see a full list of the changes in the release notes here.

“While Subversion simplifies development and helps teams seamlessly collaborate, it has had limited merge capabilities, leading some developers to choose other SCM systems,” said David Richards, WANdisco CEO. “Subversion 1.8, under the development leadership of Julian Foad, has addressed those issues and users will greatly appreciate the powerful new features.”

To save you the hassle of compiling from source you can download our fully tested, certified binaries free from our website here:

WANdisco’s Subversion binaries provide a complete, fully tested version of Subversion based on the most recent stable release, including the latest fixes, and undergo the same rigorous quality assurance process that WANdisco uses for its enterprise products that support the world’s largest Subversion implementations.

Using TortoiseSVN?

Following last weeks acquisition news, we’re very pleased to announce that TortoiseSVN 1.8 is available for free download now, and is fully compatible with Subversion 1.8.

You can get your hands on it here: is now part of WANdisco!

You may have seen the news release earlier today, advising that WANdisco has acquired, home to the world’s most popular Subversion client for Windows, TortoiseSVN.

We’re excited about this for a number of reasons:

– TortoiseSVN is an award-winning open source Subversion client software for Windows with millions of users.

– We (WANdisco) have been a major contributor to the TortoiseSVN project since 2010.

– We already support customers who are quite happy with TortoiseSVN, and want to continue using it.

– We’ve had a dedicated TortoiseSVN section on our popular Subversion forum for a while now so we’re familiar with a lot of the issues users face and the new features they’re looking for.

– This acquisition, along with our cross-platform Subversion client, SmartSVN, puts us in a great position to help drive development of features users will love, regardless of their environment.

As part of the acquisition Stefan Küng, the lead developer on the TortoiseSVN project since the start, has joined the ‘Disco to continue development on TortoiseSVN.

Welcome aboard Stefan, and the TortoiseSVN community!

Subversion Live 2013 Registration Open!

We’re back! WANdisco is proud to announce the return of our popular conference series, Subversion Live for 2013 along with a roster of new and returning community experts.

This year’s conference will start with a keynote speech from Apache Software Foundation Director Greg Stein and sessions will cover new merge features in Subversion 1.8, insight into future releases, and the future of the open source software in general. Expert-led presentations, live demos, and an in-depth committer roundtable will give attendees a unique opportunity to learn from and interact with Subversion core committers.

Sessions include:

  • What’s new in Subversion 1.8

  • The Flow of Change: How Software Evolves

  • Subversion: The Road Ahead

  • Practical TortoiseSVN

  • Move Tracking

  • Benchmarking Subversion

  • Apache Bloodhound

  • …and more!

Stefan Furhmann presenting at Subversion Live last year


Registration is open for Subversion Live BostonSan Francisco, and London being held October 3rd, 8th, and 16th respectively. Follow @WANdisco and @uberSVN for up-to-date news on Subversion Live 2013.


Subversion Live roundtable


Two New Apache Subversion Releases

The Apache Subversion team has announced two new releases: Subversion 1.7.10 and 1.6.23.

Subversion 1.7.10 includes a number of fixes, such as improving the error messages for fatal errors. Others include:

– a fix for the “no such table: revert_list” error in ‘svn revert’

– multiple fixes for ‘svn diff’ showing incorrect data

– a fix for repository corruption issues on disk failure in Windows

– svnserve exit and memory issues

More information on Apache Subversion 1.7.10 can be found in the Changes file.

Meanwhile, Subversion 1.6.23 includes a fix for svnserve exit issues and other minor bug fixes, all of which can be found in the Changes file.

Both versions can be downloaded free via the WANdisco website.


If you have any feedback on the WANdisco binaries, or on Subversion itself, head on over to our SVNForum.