Storage Area Network (SAN), Cloud Storage, and Storage as a Service (STaas)

- Storage Area Network (SAN)

Storage availability and accessibility are key issues in enterprise computing. For many enterprise applications, traditional direct-attached disk deployment within a single server may be an easy and inexpensive option, but the disks -- and the important data they contain -- interconnect with the physical server through a dedicated interface such as SAS bind. Modern enterprise computing often requires a higher level of organization, flexibility, and control. These demands have driven the development of storage area networks (SANs). 

SAN is an acronym for Storage Area Network. A SAN consolidates storage into a single storage area separate from the local area network (LAN). Computers and devices connected to the SAN can access storage devices such as tape libraries and disk arrays available on the SAN server as if it were local storage.

A SAN is a dedicated, independent, high-speed network that interconnects and provides a shared pool of storage devices to multiple servers. Each server can access the shared storage as if it were a drive attached directly to the server. 

A SAN is typically assembled from cables, host bus adapters, and SAN switches that connect to storage arrays and servers. Every switch and storage system on a SAN must be interconnected.

- Cloud Data Storage 

Cloud storage is a cloud computing model in which data is stored on the Internet through cloud computing providers, who manage and operate data storage as a service. It is delivered on-demand with immediate capacity and cost, eliminating the need to purchase and manage your own data storage infrastructure. This gives you the agility, global scale, and persistence of "anytime, anywhere" data access. 

Cloud storage is purchased from a third-party cloud provider that owns and operates data storage capacity and delivers it over the Internet on a pay-as-you-go model. These cloud storage vendors manage capacity, security, and durability so your applications can access data anywhere in the world. 

Applications access cloud storage through traditional storage protocols or directly through APIs. Many vendors offer complementary services designed to help collect, manage, secure, and analyze data at scale. 

There are three types of cloud data storage: object storage, file storage, and block storage. Each has its own advantages and has its own use cases:

• Object Storage - Applications developed in the cloud often take advantage of the enormous scalability and metadata properties of object storage. Object storage solutions such as Amazon Simple Storage Service (S3) are ideal for building modern applications from scratch that require scale and flexibility, and can also be used to import existing data stores for analysis, backup, or archiving.
• File Storage - Some applications require access to shared files and require a file system. Network-attached storage (NAS) servers typically support this type of storage. File storage solutions such as Amazon Elastic File System (EFS) are ideal for use cases such as large content repositories, development environments, media storage, or user home directories.
• Block Storage - Other enterprise applications such as databases or ERP systems often require dedicated low-latency storage for each host. This is similar to Direct Attached Storage (DAS) or Storage Area Network (SAN). Block-based cloud storage solutions such as Amazon Elastic Block Store (EBS) outfit each virtual server and provide the ultra-low latency required for high-performance workloads.

- Storage as a Service (STaas)

Storage as a Service, also known as "STaaS", is a managed service where a storage provider provides storage space to customers. In the STaaS model, the storage provider handles most of the complex aspects of long-term bulk data storage—hardware cost, security, and data integrity. Today, STaaS is used by a variety of businesses and can be integrated with some of the best storage management software available on the market today.

STaaS can be used for a variety of purposes, from long-term archival storage to short-term bulk data transfers. Because STaaS is software-defined storage, the storage capacity available to customers can easily vary and can be expanded in a short period of time without the capital expenditures required to purchase additional servers.

Today, most STaaS providers will use the public cloud to store data. There are many advantages to leveraging cloud storage, not least that cloud-based storage is easier to integrate with cloud-based applications that rely on this data. For example, if a company uses cloud-based accounting software, linking it to a cloud-based STaaS system can reduce the latency required to process this data. 

Cloud-based STaaS also provides customers with a wide range of capabilities and additional services that can be executed without the expertise of storage engineers. These include disaster recovery, data backup, data storage, mass data transfer, block storage and SSD storage, and more.