SAP offers two approaches for deploying SAP HANA on premise - the In-Memory Appliance and the Tailored Data Center Integration (TDI) approach.
The In-Memory Appliance approach, often referred to as the “all-in-one-box approach”, lets customers leverage SAP and their certified hardware partners
to deliver a pre-configured HANA system and its components. On the other hand, the TDI approach leaves the installation and the maintenance of the OS and HANA appliance to the discretion of the customer (within boundaries established by SAP). As with everything in the IT world, they’re pros and cons of both approaches and it will depend on an organizations use-case and scenario to determine best fit.
With the In-Memory Appliance approach, the hardware and software are installed and maintained by SAP and their hardware partners. As a result, customers will continue to benefit from both parties’ expertise post installation, by means of on-going support and maintenance. While this reduces the responsibility of the client, it also comes with a greater cost up-front. For companies that have the budget and / or have constraints re-using their pre-existing IT landscape, this is a viable option. However, the in-flexibility of the In-Memory Appliance approach leads some customers (and initially SAP who introduced the first phase of the TDI approach back in 2013, to provide a more flexible and HANA openness approach) to explore the TDI option.
In contrast to the all-in-one-box approach, TDI enables customers to re-use existing hardware if its deemed certified by SAP. This could provide a substantial upfront cost-savings by not having to purchase new hardware, as well as potentially avoiding pre-maturely decommissioning hardware within your company’s infrastructure. However, the risk and customer responsibility is a con that organizations need to be aware of. The software install is performed by the customer, but only an SAP certified specialist (one who has the installation certification exam, SAP Certified Technology Specialist (Edition 201X) - SAP HANA Installation) is qualified to perform the install. In addition to coordinating a consultant to install HANA, the customer is on the hook for supporting the software and responsible for negotiating terms with OS hardware partners for solution maintenance and support. A headache some clients might want to avoid.
While it’s up to the customer to weigh the pros and cons, SAP has done a good job of getting all the required information available by means of whitepapers and other documentations.