According to whistleblower Peiter Zatko they had two datacentres.

He reports that they were worried that if a DC went offline they might not be able to bring it back up again!

Their servers in their DCs were running unpatched operating systems with no disk encryption!

I highly recommend reading his full report. The level of disfunction he reports is insane.

I don't think most of the issues mentioned are mitigated by AWS, sadly.