Compared to on-premises server administrators, who can work directly with server software controls, Microsoft 365 administrators use web-based remote interfaces to work with cloud services. Microsoft 365 admin center provides access to the various tools for all the services included in the product, such as Exchange Online admin center and SharePoint admin center, as shown in Figure 2-11. These tools enable managing configuration settings and creating virtual resources, such as mailboxes and directory service objects.

FIGURE 2-11 Admin center access through Microsoft 365

However, administrators of cloud services do not have access to the underlying resources on which the services run. They cannot access the operating system of the computers on which their services are running, nor do they have direct access to the files and databases that form their service environments. For example, while administrators can create mailboxes for users in the Exchange Online admin center, they cannot access the mailbox databases containing the users’ messages.

The web-based interfaces are not necessarily a drawback for all administrators. It is entirely possible to manage a cloud-based service without ever requiring access to the service’s underlying data structures. In addition, Microsoft maintains responsibility for those data structures, ensuring their availability and security. In an on-premises service deployment, it is up to the local administrators to replicate the data structures for high availability purposes and implement a load-balancing solution to maintain a similar level of performance.

Here again, the differences between the two service environments depend on the experience and preferences of the people responsible for them. Experienced Exchange Server administrators, for example, might be wary of using a cloud-based Exchange implementation that would isolate them from the servers, the operating system, and the traditional Exchange controls. However, an administrator relatively new to Exchange might welcome the simplified access the Exchange Online admin center provides.

Deployment
A cloud-based service is always simpler to deploy than an on-premises server-based product because the service is provided to the subscriber in an installed and operational state. There is no need to design an infrastructure, obtain hardware, or install server software. An administrator can begin to work with the service immediately after subscribing to it, creating user objects, Exchange mailboxes, or SharePoint sites that are up and running in minutes instead of days or weeks.

Updates
One significant advantage to using the cloud-based version of any of these applications or services is that they are regularly and automatically updated with the latest software version. Administrators are relieved of the need to download, evaluate, and deploy updates as they are released. With a cloud-based solution, an organization subscribes to a service, not a software product, so the provider is responsible for maintaining and updating the service’s functionality. In many cases, the cloud-based version of a service receives new features sooner, and on-premises software products might not receive certain features at all.

For an on-premises service installation, a responsible update strategy requires testing and evaluation of new software releases and might require service downtime for the actual update deployments. you can get the full study guide at https://www.acedexam.com/ms-900-microsoft-365-fundamentals/

Cost
Costs—both initial and ongoing—are another decisive factor in deploying any of these services. Cloud-based services require the payment of a regular subscription fee, and sometimes there are additional fees for add-on features. A subscription allows organizations to implement a service with a minimal initial outlay because no hardware costs or server licenses are required.
Fees for cloud-based services are predictable and simplify the process of budgeting. Installing the equivalent on-premises service is a more complicated affair. An organization obviously must first purchase the server software license and the computers on which the software will run, as well as an operating system license and client access licenses for all the users. This can be a significant initial outlay.

Depending on the organization΄s requirements, there might also be additional costs. A large enterprise might require multiple servers to support different physical sites, multiplying the initial outlay cost. Backing up data and storing it also adds to the cost.

There are also fault tolerance and disaster recovery issues to consider. By default, most cloud-based services from Microsoft are supplied with a 99.9 percent service level agreement (SLA), meaning the service will experience no more than 0.1 percent of downtime in a given period. The infrastructure Microsoft uses to maintain that consistent performance is of no concern to the subscriber. Duplicating that performance level with on-premises servers will require redundant hardware and possibly even datacenters. Not every organization requires this same level of consistent performance, but even a more modest uptime guarantee will increase the expenditure for an on-premises solution.
Finally, there is the issue of the people needed to design, install, and maintain on-premises services. For example, deploying Exchange servers is not a simple matter of just installing the software and creating user accounts. Depending on the organization΄s size, multiple servers might be needed at each location, and the design and configuration process can require administrators with advanced skills. These people will be an ongoing expense throughout the life of the service.

While cloud-based services can provide a great deal of performance for the price, this is not to say that they are always cheaper than on-premises servers. In the long term, cloud-based services can reach a point where they are more expensive. Cloud service fees are ongoing and perpetual, and while expenditures for on-premises servers might begin with a large initial outlay, they can come down to a much lower level once the servers and the software have been purchased and deployed.
A comparison of the relative costs also depends on the organization΄s requirements and existing infrastructure. For a large enterprise that already maintains datacenters in multiple locations with experienced personnel, deploying a new service in-house might be relatively affordable. The initial outlay for an on-premises service might be unfeasible for a newly formed company with no existing IT infrastructure.