Comments on: Five Nines is Still Not Enough

By: Ian

Ian — Tue, 16 Dec 2008 16:41:17 +0000

Five nines is very hard to implement but also very expensive. I've written an article also about Five nines on my blog.

By: Anonymous

Anonymous — Mon, 30 Jun 2008 11:27:05 +0000

Build the website with erlang. With erlang it is possible to build services with 5 nines, including planned maintenance.

By: Ed Byrne

Ed Byrne — Sun, 29 Jun 2008 13:24:20 +0000

Of course 5 nine's is possible for a web service! It may not be possible for a single provider however. I think the future of Cloud Computing will be in multi-vendor deployments, where for example a web application can be distributed between Amazon's Cloud, Googles App Engine and other Cloud Platform's (plug Hosting365's Cloud in Dublin, Ireland here!) and therefore not reliant on the uptime of any single supplier.

The issue then becomes the application itself and if it is patched and a problem arises across the multiple sites, then the site is down. I think there a simple ways to mitigate this though - always have a second site stable version of the application that can fail-over too in the event of an update crashing it.

By: Jim

Jim — Sun, 29 Jun 2008 09:34:43 +0000

I agree and disagree. I agree that 99.999 percent uptime is not possible since it is not measurable. I disagree that simply because Amazon is not perfect that a given service system cannot be perfect. I also believe that perfection is cheaper than imperfection. One need only look at the total cost of a system failure in engineering time, customer time and lost to reputation.

It is far too easy to say zero failures is not possible. When was the last time you rebooted your HP calculator? or the GPS network was down?

By: Andrew Braae

Andrew Braae — Sat, 21 Jun 2008 22:36:59 +0000

Totally agree. Amazon’s recent cloud services outages proved that even for an organisation of their scale, achieving five nines is simply impossible. Add to that the fact that the typical end user on a web browser experiences perhaps three nines, and you can see the inanity of the many companies that actually do claim to achieve five nines – strangely none offer audited proof of their achievements! What is more important is application design that attempts to address outages. If your system effectively empties the user’s shopping cart all over the floor when there is a stoppage, then you have turned the duration of the outage as perceived by the user from a 2 minute one to a ten minute one – and infuriated them to boot as they re-key all of their data.

By: Dan Skwire

Dan Skwire — Sat, 21 Jun 2008 15:52:18 +0000

There are many ways to shrink outage durations, no matter whether the outage was scheduled (planned) or unscheduled (whoops…!). It takes a study of the times consumed in the outage, in its various phases. Shrink each phase, or any phase, and outage duration is reducad, uptime is increased, and we are … closer …. to all those nines…

When it comse to unscheduled outages, one must debug and resolve the problem that caused that ourage, rapidly. It is a lost art, perhaps, but it can be regained (yes, I can help). Problems DO OCCUR! Expect them! Use pre-existing system features to capture root-cause information, and obtain products that supplement that. BUt gee whiz, prolbems do occur, you know. EXPECT THEM!