When it comes to DNS aliasing my experience has always been to limit the number of aliases in use and have a single A record per host then setup aliases using CNAMEs for secondary references. I started researching as I have seen this method as well as setting up multiple A records pointing to a single host IP address. I was surprised to find that there is indeed a strong argument for both sides debating management/performance/lookup functionality.
If you have experience with DNS and aliases I would be interested to know the EE community input on this topic.
PROS vs CONS:
Multiple A Records to Single IP Address Aliasing
A Record Definition - Domain Name to IP Address Resolution
Management - If server IP address needs to be changed all A Records need to be updated as well to the new IP address
Performance - DNS server resolves single name to get IP address
Reverse Lookup - If using multiple A Records to point to a single IP address there will only be 1 reverse lookup pointer
Multiple CNAMES to Single A Record Aliasing
CNAME Record Definition - Domain Name Alias to Primary Domain Name A Record IP Address Resolution. Canonical name records were designed to alias A records
Management - Easier to manage server IP address changes at single A Record for a multiple CNAME references
Performance - DNS server resolves 2 names before getting IP address putting more load on the resolver
Reverse Lookup - Clear understanding that this is an alias and what host it is pointed to
Defined - Domain Name Alias -> Domain Name Alias -> Primary Domain Name A Record IP Address
Management – Multiple records to reference. Changes along the chain could break name resolution
Performance - DNS server resolves many names before getting IP address