Best practices for proactive backup strategies and disaster preparedness?

Hey everyone, I just launched my very first SaaS application a few weeks ago, and honestly, I'm feeling pretty overwhelmed by all the server management stuff, especially when it comes to backups. I had a minor scare recently where I almost lost some critical config files after a botched update, which really highlighted how much I lack a robust strategy.

My current backup setup is super basic – just manual daily snapshots of my main VM. I'm completely new to all of this and I'm really worried about proper disaster preparedness. What would happen if my main server went down completely? How quickly could I actually recover? I'm also totally unsure how to effectively test my backups to ensure they *actually* work when needed, without messing up my live service.

I keep imagining a scenario like this when I try to restore, which is terrifying:

[2023-10-27 09:30:01] ERROR: Backup integrity check failed for /var/www/my-saas/data
[2023-10-27 09:30:02] WARNING: Restore operation aborted. Data corruption detected in snapshot_20231026.
[2023-10-27 09:30:03] CRITICAL: Cannot proceed with recovery. Please verify backup source.

Could anyone share their essential proactive backup strategies and tool recommendations for a small SaaS? Specifically, how often should I back up, what kind of offsite storage is best (AWS S3, Google Cloud Storage, something else?), and most importantly, how do you guys effectively test your recovery process without disrupting live services?