Re: Ho hum
"I said to set up *your* datacentres in an active/active mode rather than an active/passive mode."
You can set up DBs in an active-active mode... and it isn't all that difficult to do. The problem is that it kills performance as you would need to write to the primary DB... then the primary DB would synchronously send that write to the second DB... the second DB would acknowledge to the primary that it has, indeed, written that data... then the primary could start on the next write. For every single write. Happening at ms rates, but it will have a performance impact if you are doing it in any sort of high performance workload. It is also really expensive as it involves buying something like Oracle Active Data Guard or comparable. You can also have multiple active DBs in an HA set up with RAC, assuming you are using Oracle. Problem there is 1) Really expensive. 2) The RAC manager evicts nodes and fails about as often as the DB itself so kind of a waste of effort. 3) All RAC nodes write to the same storage. If that storage name space goes down, it doesn't help you to have the DB servers, with no access to storage, still running.
The way to do it is to shard and cluster a DB across multiple zones/DCs... or Google just released a DB called Spanner, their internal RDB, which is on a whole new level. Really complicated to explain, but impressive.
Biting the hand that feeds IT
