Results tagged “google”

The term "Warehouse-Scale" Machines has been coined.  The term describes the specific design that sites like Google use.  The data centers that Google runs aren't like other data centers where each rack has a mish-mosh of machines that result as various people request and fill rack space.  It's more like a single huge machine running many processes.  A machine has memory, CPUs, and storage and buses that connect them all.  A warehouse-scale machine has thousands of machines all with a few, specific, configurations.  You treat the machines as CPUs and/or storage; the network is the bus that connects them all.

There is a new on-line book (108 pages!) by the people at Google that are in charge of the Google data center operations (disclaimer: Urz is my boss's boss's boss's boss's boss)

The Datacenter as a Computer: An Introduction to the Design of Warehouse-Scale Machines
by Luiz André Barroso and Urs Hölzle, Google Inc.


As computation continues to move into the cloud, the computing platform of interest no longer resembles a pizza box or a refrigerator, but a warehouse full of computers. These new large datacenters are quite different from traditional hosting facilities of earlier times and cannot be viewed simply as a collection of co-located servers. Large portions of the hardware and software resources in these facilities must work in concert to efficiently deliver good levels of Internet service performance, something that can only be achieved by a holistic approach to their design and deployment. In other words, we must treat the datacenter itself as one massive warehouse-scale computer (WSC). We describe the architecture of WSCs, the main factors influencing their design, operation, and cost structure, and the characteristics of their software base. We hope it will be useful to architects and programmers of today's WSCs, as well as those of future many-core platforms which may one day implement the equivalent of today's WSCs on a single board.

Google has enabled IPv6 for most services but ISPs have to contact them and verify that their IPv6 is working properly before their users can take advantage of this.

I'm writing about this to spread the word.  Many readers of this blog work at ISPs and hopefully many of them have IPv6 rolled out, or are in the process of doing so.

Technically here's what happens:  Currently DNS lookups of return A records (IPv4), and no AAAA records (IPv6).  If you run an ISP that has rolled out IPv6, Google will add you (your DNS servers, actually) to a white-list used to control Google's DNS servers.  After that, DNS queries of will return both an A and AAAA record(s).

What's the catch?  The catch is that they are enabling it on a per-ISP basis. So, you need to badger your ISP about this.

Why not just enable it for all ISPs?  There are some OSs that have default configurations that get confused if they see an AAAA record yet don't have full IPv6 connectivity.  In particular, if you have IPv6 enabled at your house, but your ISP doesn't support IPv6, there is a good chance that your computer isn't smart enough to know that having local IPv6 isn't the same as IPv6 connectivity all the way across the internet.  Thus, it will send out requests over IPv6 which will stall as the packets get dropped by the first non-IPv6 router (your ISP).

Thus, it is safer to just send AAAA records if you are on an ISP that really supports IPv6.  Eventually this kind of thing won't be needed, but for now it is a "better safe than sorry" measure.  Hopefully if a few big sites do this then the internet will become "safe" for IPv6 and everyone else won't need to take such measures.

If none of this makes sense to you, don't worry. It is really more important that your ISP understands.  Though, as a system administrator it is a good idea to get up to speed on the issues.  I can recommend 2 great books:
The Google announcement and FAQ is here: Google announces "Google over IPv6". Slashdot has an article too.
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