Terracotta Discussion Forums

Hi

Just joined as a new user looking for some advice regarding mirror groups.

Our application is active/active across multiple datacentres. Due to the design the belief is we'd require multiple Terracotta servers across our datacentres as each node in our cluster needs to be aware of the others cache in the event of failure.

Reviewing Terracotta it appears mirror groups is the way to achieve this with multiple active servers otherwise in an active/passive setup we'd have nodes querying remote datacentres for the cache which we believe would be undesirable.

My question is are mirror groups provided as part of the Open Source version of Terracotta? The Open Source/Commercial differences matrix http://www.terracotta.org/open-source/ suggests is it part of the Open Source version as it clearly states below.

Terracotta Software Open Source Commercial

Terracotta server to provide coherent scale and HA for all technologies Yes Yes

Seamless performance, scalability, and data management for single node applications, large datacenters, and cloud deployments Yes Yes

but the documentation and posts on this forum suggest it isn't.

http://www.terracotta.org/documentation/3.1.x/product-documentation-15.html
For capacity requirements that exceed the capabilities of an two-server active-passive setup, expand the Terracotta server array using a mirror-groups configuration. Using mirror groups with multiple coordinated active Terracotta server instances adds scalability to server array.
Scalable server arrays are available in enterprise versions of Terracotta.

Which is correct?

1. Only a single mirror group can be used via the OSS Server array project. Multiple Mirror groups is available in Ehcache FX (or any FX product...FX == multiple mirror groups among other features).

2. Multiple mirror groups is not the best way to do multi datacenter. There's actually a transparent WAN replication feature available to FX customers for this exact purpose.

I recommend emailing sales or info for more help.

Hope this helps :)

--Ari

Thanks for the response I think it does.

Terracotta is being evaluated for possible use but to clarify are you stating that if we require the use of multiple active Terracotta servers or transparent WAN replication then the open source version won't be able to meet our requirements. We will need to trial the commercial version with a view to purchasing a license?

Are you one of the developers for the product?

Many thanks

your clarification is exactly correct. If you need multiple stripes, you need the paid version. You also correctly pointed out you can work with a free trial of the paid version and decide if it is good / works for you before you have to pay.

I work at Terracotta, yes. Develop the product? Not really. I am CTO. Do CTO's really do anything _good_?

Cheers,

--Ari