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Most of persistent data is stored in RDS. This implies the data is highly available as it is replicated synchronously in two availability zones, however it is certainly not impossible to lose an entire region e.g. due to natural disaster etc. In addition to relying on multi-AZ functionality we also save and encrypt daily full mysqldump to cloudboss (in us-east-1b AZ) here: https://cloudboss.mifos.org/cloud In the event of disaster you would need to download and decrypt the snapshot and create a new RDS instance and follow the instructions that apply when migrating an MFI from the old infrastructure.
Point in time recovery
RDS supports point in time recovery. We configure each RDS instance to store up to 8 days of PITR logs. However this feature in our trial runs can be really slow e.g. 9 hours or so to do a restore. As an alternative you can use the mysqldump snapshots from above.
Front-end
Application server (Tomcat/Jetty). What clients hit.
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