Data resiliency in Office 365

Most organizations have either questions or requirements around retention, backup, compliance, and recoverability. Microsoft addresses these concerns through a framework of data replication, physical backups, and highly available or fault-tolerant designs. Resiliency refers to the concept of being able to continue to provide services, regardless of the types of failures that occur.

Microsoft’s goal in Microsoft 365 is designed with the following five data resiliency principles in mind:

• Critical and non-critical data: Critical data (such as content) must be preserved at all costs against loss or corruption.

• Fault domains: Data must be separated into as many fault zones as possible to provide failure isolation.

• Atomicity, consistency, isolation, and durability (ACID) test: Data must be monitored to detect whether it fails the ACID test. ACID is a set of properties that ensures the validity of a data transaction.

• Corruption protection: Customer data must be protected from corruption. To ensure that data is in a continuously good state, it must be scanned or monitored, repairable, and recoverable. This includes physical and logical monitoring at both the hardware and software layers.

• Data recovery: Allow customers to be able to recover their own data. Tools are provided to allow customer autonomy when recovering accidentally deleted data.

Microsoft 365 addresses the potential for data corruption (whether due to hardware or human, application, or operational errors) by replicating data and performing continuous checks on transactions to ensure that they are valid. In addition, during the development stages of applications and services, Microsoft conducts thorough code reviews to ensure that all code contributes to the overall efficacy of the system. Application data is monitored and replicated so that transactions can be rolled back to previous good states if necessary.

In addition to corruption, malware and ransomware present challenges to both on-premises and cloud environments. Microsoft 365 uses mechanisms to prevent malware from being introduced through clients or servers, including both heuristic and signature-based detection. Microsoft 365 environments are scanned at regular intervals as well as during times when files are downloaded, opened, or executed. SharePoint Online and OneDrive for Business each include document versioning, which can be used to recover files that may have been encrypted, and Cloud App Security can be used from a customer’s perspective to detect anomalous behaviors executed in their environments.

Microsoft 365 also makes use of extensive monitoring with native, third-party, and open source products, using data analytics to predict problems, and performing synthetic transactions to verify that services are responding correctly.

In the next section, you will dive deep into the information protection features.