I believe MySQL's working directory is on EBS, so yes, even temporary tables would be on EBS -- don't quote me on that, though.
Re: outages, we use multiple replicated servers in different availability zones -- an outage is usually (though not always!) limited to a single zone. For a region-wide outage, we have emergency backups being sent to a different AWS region (east -> west), and if shit completely hits the fan we have off-AWS backups.
Re: outages, we use multiple replicated servers in different availability zones -- an outage is usually (though not always!) limited to a single zone. For a region-wide outage, we have emergency backups being sent to a different AWS region (east -> west), and if shit completely hits the fan we have off-AWS backups.