Traditionally, storage was confined to the server's hardware; eventually, due to the increasing demand for storage capacity, availability, and centralized management, there was a need for a robust system to manage storage provisioning and maintenance. This lead to the evolution of storage area network (SAN) and Network Attached Storage (NAS). While a typical Fiber Channel, SAN, proved to be quite expensive, particularly the Fabric switch and the array itself, it also had other form factors that leveraged the existing network infrastructure in the form of iSCSI and NFS. Interestingly, a complete cycle of evolution is taking place and we are heading back toward storage being confined to the server and forming one of the methodologies of achieving Software-Defined Storage.
In a typical data center, we have several types of resource-intensive workloads that can be compute-, network-, memory-, or disk- intensive. While the compute and network needs are serviced by server virtualization solutions, such as ESXi, and network virtualization solutions, such as NSX, all the workloads need disk capacity, but with varying requirements in terms of redundancy and performance. The storage resources need to be elastic and dynamic, catering to different I/O requirements.
This implied that we needed a much more granular and dynamic management of the storage infrastructure, and such a degree of control can only be achieved at the software stack; we needed Software-Defined Storage.
Very simply put, Software-Defined Storage can be defined as a storage infrastructure that can be fully managed at the software stack.
Software-Defined Storage is truly aligned with the SDDC vision of the abstraction, pooling and automation of all the data center's resources.
The deliverable of Software-Defined Storage is a Virtual Data Service that is policy - driven; the three primary attributes of this deliverable are:
Performance
Data protection
Mobility
While the SDS market is densely populated with various different players, the market is highly disruptive and evolving heavily, we will look at a few form factors available as on date.