I've got a single domain. I moved my nameservers to AWS R53 yesterday. These are A record, alias'd to my ELB > EC2s.
However, occasionally, and mostly on subdomains I get drop out. It just could not be found.
Also, what appears to only happen on subdomains... I get really slow responses. This is not EC2 related, the www. responds super quick. And my carbon copy site works fine elsewhere, also pre-R53 loaded in normal speed.
I've done live HTTP headers and monitored logs, nothing hits the box until it visibly begins loading. So, it's obviously in the DNS realm. I'm not a great packet sniffer, so looking over Wireshark/Ethereal logs, I can only see whois and then standard queries to domain. Bit messy to work out what's going on.
Any advice or pointers in which to try and follow this problem up would be greatly appreciated.