We have all heard (and gnashed our teeth over) that in order to get a proper automatic failover environment for Oracle (i.e Data Guard) we need Enterprise Edition. Oracle Enterprise Edition (or as Brent Ozar so succinctly put it: Expensive Edition) is hideously expensive, especially if you’re only ever going to use the Data Guard feature.
Sure, you can always use the classic Oracle Standby with a bunch of scripts – much like log shipping in SQL Server. It works (if your scripts are OK this is basically bomb-proof) and is fairly simple to set up. Trouble is that there is no (good) way of automating the failover, and when itis time to go back, well, you’re basically looking at a complete rebuild of the database previously known as the primary. Depending on your the amount of data this can take a long time, as well as saturate the network links between the systems (and the rest of the datacenter), making end users (and sysadmins) less than overjoyed.
Oracle is a huge company and different divisions peddle different software – the database people don’t sell applications, the application people don’t sell databases, and neither of them sell … Golden Gate. Golden Gate is the result of a company purchase Oracle did several years ago, and Golden Gate is an exceptionally versatile data transfer tool. It is mostly used for heterogenous data transfer (that is, going from one database engine to another) or basically anything that involves massaging the data. That’s probably why so few people think of it when it comes to – yes, you guessed it – high availability.
First things first – what is it going to cost me? Well, the answer is ‘a lot’. But not nearly as much as a complete Enterprise Edition solution. Golden Gate is licensed per core, just like Enterprise Edition, but has a price tag of roughly half of an Enterprise Edition core license. That means that you will be paying A LOT more for Golden Gate than for your Standard Edition database, but again, not nearly as much as if you’d decided to bite the bullet (hailstorm?) and forked up the cash for an all-Enterprise Edition setup.
Golden Gate brings a lot of cool stuff to the party as well – remember the ‘heterogenous’ part of the previous paragraph? Oh yes, that means that we can use Golden Gate to sync up two different Oracle versions. Thinking slightly outside the box, this means that we can use this solution for a transparent upgrade without any downtime at all. Or we can do data transfer between the Oracle databasen and, say, an SQL Server data warehouse. Or, that you came here for – a plain, simple Data Guard analogy with automatic failover.
This is just a teaser of WHAT you can do, not HOW you do it. I’ll make a blog post about that in the future!