Planning for Disaster

How to plan for disaster:

High Availability → Architect for High Availability, providing redundancy and fault tolerance.
Backup → Critical part to protect data and ensure business continuity.
Disaster Recovery → Preparing for and recovering from a disaster.
- Anticipate failure and refine operational procedures frequently.
- Test recovery procedures and automatically recover from failure.
- Recovery Point Objective (RPO) → Maximum acceptable data loss, measured in time.
- Recovery Time Objective (RTO) → Time it takes to restore apps and recover data, measured in time.

Storage Recovery

Object Storage

S3 buckets exist in a specific region (with replication within up to 3 AZs), you can configure Cross-Region Replication, to automatically (asynchronously) replicate objects to the destination bucket.

https://lh5.googleusercontent.com/kfZgbSzjvWTOatmfTuFRp0j0p0yTju53CgscNNseDUKc4tBNYtfBZ_OtfPiE4U-XXOB6gp602Ny0LartRsaJSCKy34Lwfxl2iv-fJKUzOnMj5fUIv67By_o_HDXDlLzo94b2Yql_

Block Storage

Can backup EBS volumes to S3 by making snapshots of the volumes (only the changes are stored in the snapshot). EBS volumes are also replicated across multiple AZs in a region. The S3 snapshot can be replicated across multiple regions.

https://lh6.googleusercontent.com/WG3bKg4zqt3r1B1zxxoeqvRWUxvJX4f9V8vySRy9CJ0zgJyQEnmCl7RqCdlgYi6OUediSC4rdBWs1WNYFjSXk2ECqnVFMU_G29ljgz1raDXfyfyFbq4gt6AOzT7hY9q96s7-yu_r

File Storage

Replicate File Storage across multiple regions using AWS DataSync for these operations. Also you could replicate on-premise filesystems on the cloud.

https://lh4.googleusercontent.com/s1ZWqodV0ptS0ksMFYUeUxuc005M73LxSsr8cD-L9NDTjj0qNEGWQC7qQ6PAS3vfnmRJHCVnrSkeC5bllfCAMHv1Ey5XtZAAqBcwEpcSwWd1GsktuGDWcVVBE_2uUpgxppSlljfw

AWS Backup

Configure backup policies and monitor activity for AWS resources and on-premise resources (cannot be fully on-premise, needs at least a part in AWS). It can copy across AWS accounts and regions, add cost-allocation tags, and transition to lower-cost storage options.

Central place to configure backups of resources.

AWS Storage Gateway

Hybrid storage service to enable on-premises applications to use cloud storage. Has optimized data transfer mechanisms.

Types of gateway → All stored in S3 but with different interfaces:

File Gateway → Store and retrieve with a local cache, and can be accessed through an NFS mount point (NFS / SMB).
Volume Gateway → Block storage disc volumes, stored as point-in-time EBS snapshots (iSCSI).
Tape Gateway → Virtual tape library that can be archived (VTL / iSCSI).

Compute Recovery

EC2 instances can be configured to reboot to a different underlying hardware in the case of status checks giving errors. Using the snapshot capability for backups, snapshots can be created. Using the automated rebuild to make it easier to recreate the environment. Cross region AMIs and snapshot copies should be used.