使用Terracotta的人很关心它如何收费，但是官网并没有明确如何收费。只是讲划分了开源，ES，FX三大类。
Of all of Terracotta's commercial products, the Enterprise Suite provides the ultimate flexibility. It is designed for customers who have the need to solve multiple different problems within their applications. As such it includes the core Terracotta point products—Ehcache, Web Sessions and Quartz Scheduler—as well as a supported version of the core Terracotta Platform for Distributed Shared Objects (DSO).
The Enterprise Suite comes in two editions—EX and FX. FX is designed for unlimited scale. ［［［It includes the high throughput Terracotta Server Array with data striping feature to partition cache data and enables you to add scale on demand］］］. ［［［Server striping means more capacity and more throughput for your enterprise Java application］］］. Adding server array striping requires nothing more than a simple configuration change. No application changes are required.
As with all other Terracotta commercial products, the Enterprise Suite includes enterprise support, monitoring, management, and visualization.
下面是论坛时有人也提出收费问题的回答：
I've read in the documentation that it's not possible to run an active-active server array with Terracotta ES. The Terracotta FX version will lift this restrictions. But there is only a trial version for 30 days available on your page.
ES的版本不支持active-active server array。即striping feature to partition cache data and enables to add scale on demand.
FX版本有一个三十天的试用，试用之前，需要填写一个form,试用过后，terracotta的销售会与你进一步联系,确认试用有没有解决你的问题及进一步的购买。Terracotta没有在网站上明码标价的原因。
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when you claim that Terracotta is open source, and at the end I have to fill out a form to get a trial version for 30 days... So is Terracotta FX still open source?
下面的是Ari的回答：
Hmm,
Not sure what to say. Terracotta FX is not open source. Maybe you did not realize that? But since it is not OSS, it hopefully explains why the trial is 30 days, etc.
Moreover, everything you do in Terracotta ES will translate directly to FX.（FX包括ES的所有功能） It is almost a perfect drop-in underneath an app already integrated with ES. （FX可以无缝集成使用ES的应用）
Think of ES as ［［［smart-scale and FX as easy-scale］］］. ES can go very fast. We have many users doing large updates at a rate of 5K - 20K tps. FX can do more TPS but importantly, FX lets you skip some tuning and expertise-building and instead just spend money on HW on which to run Terracotta（FX简单到只需你花钱去购买硬件。HW硬件）.
So I suggest you:
(a) get integrated first,
(b) decide you like it but need to see the scale with FX
(c) if you need FX, fill out the trial request and use that to vet the scale and then
(d) make a purchase decision for FX vs. staying with ES and tuning your app by hand to get the scale.
Cheers,