Launched in 2011 with the iPhone 4S, the functional assistant Siri has proven to be one of the popular functions of iDevices, despite the fact that it understands an extremely limited number of languages and does not always recognize words that well. The entire system works with the help of a cloud-type infrastructure whose configuration was chosen by Apple, the company taking over all the recordings made by Siri for users, analyzing them and quickly providing answers to questions, performing web searches or acting on various functions of iOS.
SO one of my ex-colleague is now lead cloud architect at Apple and does know on which hardware SIRI is running so this is the infra. World is separated in region and in region got 1 Siri instance, last time I asked there were 3 siri instances for US (East coast, central, west coast ) this based on how many potential user there is per region, but there is at least 1 per country. 1 instance of siri is made of: 4 HP c7k http://www8.hp.com/us/en/products/enclosures/product-detail.html?oid=5363108#!tab=specs . Each c7k is loaded with 8 blades of this type: http://www8.hp.com/us/en/products/proliant-servers/product-detail.html?oid=5288623#!tab=features
If you've ever wondered what kind of infrastructure Apple has implemented to support Siri, well today you will find out. The American company has in its data centers "instances" with 4 racks each with server clusters dedicated to each country from which answers are sent for analysis, the USA being one of the countries where there are no less than 3 dedicated clusters, one each for the eastern, central and western parts. A cluster of this kind is composed of 4 HP C7K(BLc7000) server racks each with a list price of $31.000.
The server don't have any local disk, they boot from sAN and keep all data from SAN, if a server dies, just remove it, put another one, start, and its good to go. so if you count a Siri instance is made of: 32 servers with a total of 1024 cores, and 32 TB of RAM. The application is stateless, so no HA and DR per se, but if one server fails, just the current Siri query is lost, you just have to repeat again and your query will end up on another one server. If the full DC blew u or lost connection, this is a guess but I think each carrier will redirect Siri traffic to another region but that I can't guarantee.
In each rack of this kind there are several 8 HP ProLiant BL660c Gen8 servers customized by Apple Lossless Audio CODEC (ALAC),, each such server having a list price of $28.000. Looking only at the hardware, we are talking about 32 servers that have 1024 cores and 32 TB of RAM, they have enormous processing power, which is necessary to support the software behind Siri. Practically all 3 clusters dedicated to the USA have a list price of $800.000, and for each country on the globe the Apple company would have dedicated one cluster worth approximately $267.000.
To be honest, I find it hard to believe that Apple really has 32 dedicated servers for each country on the globe, and I imagine that Romania and similar countries share clusters of this kind without problems.
