google

When 99.999% Isn't Good Enough

When discussing availability of a service, it is common to hear the term "Five Nines" referring to a service being available 99.999% of the time but "Five Nines" are relative. If your time frame is a week, then your service can be unavailable for 6.05 seconds whereas a time frame of a year, allows for a very respectable 5.26 minutes.

In reality, none of those calculations are relevant because no one cares if a service is unavailable for 10 hours, as long as they aren't trying to use it. On the other hand, if you're handling 50,000 transactions per second, 6.05 seconds of unavailability could cost you 302,500 transactions and no one cares if you met your SLA.

This problem is one I've come up against a number of times in the past and recently even more and the issue is orders of magnitude in IT. The larger the volume of business you handle, the less relevant the Five Nines become.

Sparc Solaris 10 Jumpstart Flar DVD - Part 1

The Solaris Flash installation feature enables you to use a single reference installation of the Solaris OS on a system, which is called the master system. Then, you can replicate that installation on a number of systems, which are called clone systems. You can replicate clone systems with a Solaris Flash initial installation that overwrites all files on the system or with a Solaris Flash update that only includes the differences between two system images. A differential update changes only the files that are specified and is restricted to systems that contain software consistent with the old master image.

I ran into several issues trying to create such a DVD when following the standard Google results so I thought I'd summarize my experiences. This is a work in progress- I might hit a brick wall at some point, but I hope not.