Eric Novikoff's Blog
IT managers and pundits speak of the reliability of a system in "nines." Two
nines is the same as 99%, which comes to (100%-99%)*365 or 3.65 days of
downtime per year, which is typical for non-redundant hardware if you include
the time to reload the operating system and restore backups (if you have
them) after a failure. Three nines is about 8 hours of downtime, four nines
is about 52 minutes and the holy grail of 5 nines is 7 minutes.
From a users' point of view, downtime is downtime, but for a
provider/vendor/web site manager, downtime is divided into planned and
unplanned. Cloud computing can offer some benefits for planned downtime, but
the place that it can have the largest effect on a business is in reducing
unplanned downtime.
Planned downtime... (more)
Eric Novikoff's Blog
Are humans really necessary for maintaining SLAs? In today's cloud computing
deployments, especially with systems like Amazon's EC2, the users'
application is responsible for both measuring and taking action on
application performance issues. This complicates deployment and coding, as
well as tying your application to a particular cloud provider. However, I
believe t... (more)