What is single instance store and how does single instance store work?

[EddieHom]

I read about single instance store while studying Windows Server features. I want to understand what single instance store does and how single instance store helps save storage space.

 

[royjasika]

Single Instance Store (SIS) is a storage optimization technique that saves only one copy of identical data and replaces duplicates with references. It’s used in systems like Microsoft Exchange Server to reduce storage use. When multiple users store the same file or email, SIS keeps one copy and links others to it, improving efficiency and saving disk space.