We continue to see more evidence of the themes we discuss in our latest CAOS special report, Seeding the Clouds, which examines the open source software used in cloud computing, the vendors backing open source, the cloud providers using it and the impact on the industry.

First, as usual, we are seeing consistencies between our own research — which indicates open source is a huge part of today’s cloud computing offerings from major providers like Amazon, Google, Rackspace, Terremark and VMware — and that of code analysis and management vendor Black Duck. In its analysis of code that runs the cloud, Black Duck also found a preponderance of open source pieces, in many cases the same projects we profile in our report.

Indeed, open source software is an important part of the infrastructure, …

Have you seen error messages similar to the following:

Communications link failure – Last packet sent to the server was X ms ago.

Judging from the forums, many people have had problems with this.  Here’s a brief overview of the causes, and potential solutions.

Generally speaking, this error suggests that the network connection has been closed. There can be several root causes:

• Firewalls or routers may clamp down on idle connections (the MySQL client/server protocol doesn’t ping).
• The MySQL Server may be closing idle …

MySQL Connector/J has a useful feature which executes a lightweight ping against a server (or, in the case of load-balanced connections, all active pooled internal connections that are retained) to validate the connection. As you might guess, this feature is useful for Java apps which use connection pools, so that the pool can validate the connection. Depending on your connection pool and configuration, this can be done at different times:

• before the pool returns a connection to the application
• when the application returns a connection to the pool
• during periodic checks of idle connections

So, if you want to use this magic light-weight ping process, here’s how you do it:

Specifying a “validation query” in your connection pool that starts with “/* ping */” _exactly_ will cause the driver to instead send a ping to the server and return a fake result set (much lighter weight), …

This was bound to happen, of course. Things were going too well. At a time when Google is activating 200,000 Android phones a day, and Android has overtaken the iPhone in terms of U.S.

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There are many questions that arise out of Oracle’s copyright and patent infringement complaint against Google regarding its use of Java in Android. There are several things that make the suit significant to the entire industry: it centers not just on software copyright, but also software patents (an increasingly and hotly debated issue), the quickly-expanding smartphone market and open source software. The first question is: what is Oracle doing?

Many are speculating that this is simply an effort to further and more effectively monetize Java, a storied program language that has move more toward openness and survived several supposed death sentences as newer languages arrived. Still, with all of the open source parts — GlassFish application server, MySQL database, OpenOffice.org suite — is Java the most significant to Oracle? It may be, but regardless of what Oracle is doing, its legal moves here may certainly have an impact on the …

Connector/J has long provided an effective means to distribute read/write load across multiple MySQL server instances for Cluster or master-master replication deployments, but until version 5.1.13, managing such deployments frequently required a service outage to redeploy a new configuration.  Given that ease of scaling out by adding additional MySQL Cluster (server) instances is a key element in that product offering, which is also naturally targeted at deployments with very strict availability requirements, we had to add support for online changes of this nature.  It’s also critical for online upgrades – the other option is to take a MySQL Cluster server instance down hard, which loses any in-process transactions and generates application exceptions, if any application is trying to use that particular server instance.

Mark Matthews and I first …

In a previous blog post, I wrote about Connector/J’s failover policies, I described three triggers which cause Connector/J to re-balance (potentially selecting a new physical connection to another host):

1. At transaction boundaries (transactions are explicitly committed or rolled back)
2. A communication exception (SQL State starting with “08″) is encountered
3. When a SQLException matches conditions defined by user, using the extension points defined by the loadBalanceSQLStateFailover, loadBalanceSQLExceptionSubclassFailover or loadBalanceExceptionChecker properties.

Those conditions fit most needs very well, but there are situations where people are running with auto-commit enabled (no explicit transaction commit or rollback), and the end result is that Connector/J never …

SugarCRM. Funding for EnterpriseDB and Morphlabs. Even more core. And more

Follow 451 CAOS Links live @caostheory on Twitter and Identi.ca
“Tracking the open source news wires, so you don’t have to.”

Bittersweet
# OStatic asked whether SugarCRM has violated open source principles.

# Larry Augustin clarified SugarCRM’s approach to open source and openness.

# Savio Rodrigues advised anyone considering SugarCRM not to get hung-up on source code availability.

Funding round
# EnterpriseDB has reportedly raised $7.5m of a …

There are signals of continued problems and dysfunction — namely lack of support, organization and communication — in the OpenSolaris community. This follows on a deterioration of the OS leadership and support since Oracle bought Sun Microsystems, including the elimination of OpenSolaris CDs, one of the things that made the open source version of Solaris more like Linux.

We had speculated on the fate of Sun open source software under Oracle and while we acknowledged Oracle’s participation in, contribution and commitment to and opportunity from open source software, we …

Shortly after I wrote my last post regarding some advanced Connector/J load-balancing properties, Anirudh published a post describing configuration of RHEL LVS for load-balancing and failover of MySQL Cluster SQL nodes.  It’s an interesting post, and I admit I know very little about RHEL LVS, but it reminded me of problems I experienced when trying to set up load-balanced ColdFusion(!) servers at my last job, years back.  We ended up with a nice hardware load-balancer sitting in front of multiple ColdFusion web servers.  The problems we found were that our application depended upon session state, which was stored (of course) on a single web server.  The load-balancer allowed us to define sticky sessions, which is what we did, but it cost us.

We couldn’t really balance load – we could balance session counts, sort …