On Jun 3, 2009, at 11:15 PM, gb10hkzo-nanog@yahoo.co.uk wrote:

For example, consider the licensing and hardware costs involved in running something like Oracle Database in active/active mode (in a topology that is supported by Oracle Tech Support).

In my experience, it's no more expensive in terms of hardware/software licensing costs to run active/active, and actually less in terms of opex costs due to issues raised previously in this thread, as well as a host of others. Note that running active/active doesn't necessarily mean doing something like running a clustered database back-end, utilizing vendor- specific HA solutions. It can be done via a combination of caching, sharding, distributed indexing, et. al. - i.e., via application structuring and logic. ----------------------------------------------------------------------- Roland Dobbins <rdobbins@arbor.net> // <http://www.arbornetworks.com> Unfortunately, inefficiency scales really well. -- Kevin Lawton