云计算中的多租户是什么？

Multitenancy architecture involves a SaaS app distributing resources across each tenant but storing their data separately. All tenants within the infrastructure get updates simultaneously, and isolation levels vary. 

Many tenants use multitenancy architecture for cost-effectiveness, but it’s important to consider the trade-offs of sharing resources with others. You should look at how much flexibility you receive before signing up for a service.

租户是以下的一部分 SaaS app’s infrastructure，但它们有自己的私有空间。虽然资源在多租户云中是共享的，但租户会更改自己的设置并选择他们需要多少数据。 

Depending on the provider, you might find single and multi-tenant options offered – but the price will differ. You should think about finding a service with both so that you don’t have to migrate everything once you scale.

以下是不同多租户类型的简要介绍：

• 单实例，单数据库： This option will impact scalability, but it also costs the least money. As the name suggests, you share various resources – mainly instances and databases. 
• Single-Instance, Multiple Databases: Each tenant has their own database where they can store their data, which you may want to consider for privacy. Having some knowledge of managing these tenancy types is necessary before you start. 
• Multiple-Instance, Multiple-Databases: Tenants use the same infrastructure, but they have their own instances and databases; it typically costs more than the other options. You can upgrade to this option once you’ve built a team and/or know how to manage these. 

企业使用SaaS多租户的一些原因包括： 

• 成本：供应商和租户可以降低成本，但可能会牺牲隐私。 
• 可扩展性：基础设施会根据活动水平和需求上下调整资源。 
• 维护：更新和补丁。

以下是专用基础设施和多租户基础设施之间的主要区别： 

• Dedicated: Tenants have instances that nobody else can access, but they’re still within a cloud system.
• Multi-Tenant: Data and configuration are separate, but they share other resources.