Tuesday, November 30, 2010

Clustering between different sites / geopgraphic failover

I just completed a new feature in JGroups which allows for transparent bridging of separate clusters, e.g. at different sites.

Let's say we have a (local) cluster in New York (NYC) and another cluster in San Francisco (SFO). They're completely autonomous, and can even have completely different configurations.

RELAY [1] essentially has the coordinators of the local clusters relay local traffic to the remote cluster, and vice versa. The relaying (or bridging) is done via a separate cluster, usually based on TCP, as IP multicasting is typically not allowed between sites.

SFO could be a backup of NYC, or both could be active, or we could think of a follow-the-sun model where each cluster is active during working hours at its site.

If we have nodes {A,B,C} in NYC and {D,E,F} in SFO, then there would be a global view, e.g. {D,E,F,A,B,C}, which is the same across all the nodes of both clusters.

One use of RELAY could be to provide geographic failover in case of site failures. Because all of the data in NYC is also available in SFO, clients can simply fail over from NYC to SFO if the entire NYC site goes down, and continue to work.

Another use case is to have SFO act as a read-only copy of NYC, and run data analysis functions on SFO, without disturbing NYC, and with access to almost real-time data.

As you can guess, this feature is going to be used by Infinispan, and since Infinispan serves as the data replication / distribution layer in JBoss, we hope to be able to provide replication / distribution between sites in JBoss as well...

Exciting times ... stay tuned for more interesting news from the Infinispan team !

Read more on RELAY at [1] and provide feedback !

[1] http://www.jgroups.org/manual/html/user-advanced.html#RelayAdvanced

Tuesday, November 23, 2010

JGroups finally has a logo

After conducting a vote on the logos designed by James Cobb, the vast majority voted for logo #1. So I'm happy to say that, after 12 years, JGroups finally has a logo !

I added the logo and favicon to jgroups.org. Let me know what you think !

There's also swag available on cafepress, check it out !