Design a disaster recovery strategy

Microsoft and Azure services which can be used as part of a DR strategy include:

  • Azure Backup – scalable, off-site, encrypted backup service
    • Create a recovery vault, specify the Azure region
    • Download vault credentials
    • Download agent
    • Install agent
    • Upload vault credentials
    • Launch backup
    • Configure backup properties
    • Schedule backup
  • StorSimple – hybrid storage appliance with tiered disk storage (SSD, SATA) and Azure storage.
    • Uses de-duplication and compression techniques
    • Use for backup and DR in addition to production storage
    • Data encrypted in flight and at rest, store encryption keys on-premise
    • Storage presented using iSCSI
    • 2 physical appliances available and a virtual appliance
  • Data Protection Manager – Microsoft’s enterprise backup and recovery solution which supports Bare Metal Restore (BMR) and file level recovery.
    • Integrates with Azure by registering with the associated Azure Backup Vault
    • Use tape, local disk storage or Azure
    • Supports workloads including server, client, SQL Server, SharePoint, Hyper-V, VM, Exchange

StorSimple is the optimal solution for high performance storage and support of low RTO and RPO requirements. Azure Backup is a cost-effective, simple solution for providing block level backup and and file level restore with a supported agent. Data Protection Manager can be integrated with Azure Backup and provides additional capabilities for protecting and recovering Microsoft workloads.

Design websites for business continuity

Scale-out web apps on Basic, Standard and Premium tiers to 3, 10 and 20 instances respectively. Scale-up to provide additional resource to each instance with higher tiers increasing the limit. Azure SQL also offers Elastic Scale to scale horizontally (sharding) and vertically (250GB Standard, 500GB Premium).

CDN allows content to be replicated globally to be served up to users faster. Files are cached in local Azure Blob storage and accessed using the CDN address. This does not need to be considered when designing web applications which may refer to the original address.

Traffic Manager enables websites to be deployed to multiple regions and accessed using a single URL.

SQL Sync is a feature of Azure SQL which sychronises a database or select tables and columns on a schedule from the source to a HUB database which could be in Azure or on-premise. SQL Sync does not synchronise transactions.

SQL geo-replication allows recovery of a database to another Azure region. Standard tier provides an offline secondary, Premium tier provides up to 4 readable backups.

Web Apps allow a single backup of websites per day, Premium allows up to 50 backups per day. Web App backups will save Web App files, associated database, log files from the website and WebJobs. With Free and Basic FTP(S) or a GIT Clone URL can be used as an alternative.

When designing the data tier it is important to consider the data storage type and scaling of the data:

  • Use of relational (RDBMS) e.g. SQL or non-relational database (e.g. Azure Table Storage, DocumentDB)
  • Scale, size of database supported
  • Normalization of data vs. performance of too many linked tables
  • Backup of historic data to reduce security exposure and database size