Comparing Exchange Online and Exchange Server 2013 - M. Omer Siddiqui's Blog - Site Home

Now that Office 365 has over a year under its belt and the new Exchange is around the corner, you may be considering upgrading your on-premises email system, moving to the cloud or a combination of the two with a hybrid deployment. We’ve invested heavily in providing you with an awesome email experience and the flexibility of choosing how you’d like to deploy it.

There are a lot of important factors to consider but these factors have changed with the introduction of the new Exchange. Here’s a summary of some key factors to consider between staying on-premises and moving to the cloud, as well as some feature areas where we’ve made enhancements to make it easier for you to go to the cloud while maintaining control.

	Exchange Online for Office 365 for enterprises	Exchange Server 2013
Cost	You won’t need to worry about purchasing, upgrading and managing hardware with Exchange Online to help reduce the total cost of ownership of your email system. Updates, upgrades and 24x7 IT phone support is included. It’s also important to note that onboarding to Office 365 doesn’t mean that you will no longer need to manage hardware altogether. Many organizations will maintain an on-premises Active Directory for example, and will want to maintain AD synchronization with Office 365 and optionally, ADFS.	We’ve continued to evolve the architecture and manageability of Exchange so that it helps reduce your TCO including supporting multiple databases per volume, layer 4 load balancing, a single web-based administrative interface, reduced overhead for high availability and more. You still will need to deploy and manage Exchange software and hardware on-premises and will need to plan future hardware and software upgrades.
High availability	High availability and redundancy is built in and there is a financially-backed 99.9% SLA for Exchange Online.	We’ve enhanced managing high availability. Managing DAGs is simplified with automatic DAG network configuration, enhancements to lagged copies and management cmdlets. Based on our experiences with managing Exchange Online, we’ve added Managed Availability to help maintain a good end user experience – not just worry about server uptime.
Management & control	Manage Exchange from a single, web-based administrative experience with the Exchange Administration Center which gives you rich capabilities and a streamlined experience. Remain in control by testing out upcoming service enhancements via previews.	You get the greatest degree of control and customization on your configuration when you manage your on-premises servers including complete visibility into the deployment down to the level of server logs. In addition, you can use Address Book Policies to provide different views of the Global Address List (GAL) to subsets of users within the same Exchange Organization.
Storage	25 GB by default.	Configurable to meet your organization’s needs and policies.
Compliance	Exchange Online includes the same rich feature set as Exchange Server 2013, including eDiscovery and DLP, so you can help enforce your organization’s compliance policies. You can use transport rules and apply IRM protection with Azure Active Directory Rights Management.	You can help keep your organization safe from users accidentally sharing sensitive data with Data Loss Prevention (DLP) capabilities and allow compliance officers to run In-Place eDiscovery queries across Exchange, SharePoint and Lync from a single interface with the eDiscovery Center. You can also use transport rules and apply IRM protection with your on-premises Windows Rights Management Services implementation.
Anti-spam/ anti-malware	The next release of FOPE will be called Exchange Online Protection (EOP) and as with FOPE is included as part of Exchange Online. EOP provides inbound and outbound spam filtering, reporting, message trace, multi-engine anti-malware and mail-flow configuration features. Many new enhancements have been introduced to EOP, including management which is fully integrated into the Exchange Administration Center.	Basic anti-spam and anti-malware capabilities will be provided out-of-the-box. You can also add EOP to your deployment in order to get inbound and outbound spam filtering, reporting, message trace, multi-engine anti-malware and mail-flow configuration features. EOP management is done on a separate interface, but the user-interface will be identical to that of the new Exchange Administration Center.
Public Folders	Public Folders are now supported in Exchange Online with new, modern public folders. We’ll supply a method to help you get your legacy public folders to modern public folders in the cloud.	Modern public folders are now based on mailbox architecture so you’ll get the same storage and HA capabilities as normal mailboxes.
Security, privacy and regulatory compliance	Security and privacy are important to you, and we place great emphasis on helping protect the privacy and security of your data. Office 365 is compliant with many world-class industry standards including ISO-27001 and FISMA. Check out the Office 365 Trust Center for more information.	Exchange Server 2013 can be configured to meet virtually any compliance need and you have full control and responsibility over enforcing compliance policies and meeting your security requirements.
Migration	We’ve unified the mailbox migration toolset and management interface to help simplify the migration process to Office 365 no matter which migration method meets your needs. The hybrid configuration wizard is included right within the Exchange Administration Center.	We’ve enhanced the migration toolset which also means it’s a simpler process for moving mailboxes across databases or transitioning to the new Exchange.
Applications	Some legacy applications, protocols, third party mail-enabled programs and API’s are not supported by Exchange Online. Your organizations may need to update or retire these when opting to move to the cloud. The good news is you can customize Outlook and OWA by utilizing the new cloud-based extensibility model with Apps for Outlook. The same apps work across the new Outlook and OWA. You can discover and install apps via the Office marketplace, control which apps end users are allowed to install, and use or develop your own.	You get the highest degree of customization with managing Exchange on-premises, and you also get to leverage the new extensibility model with Apps for Outlook and the Office marketplace.