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This presents us with a double bind; each user’s content is customised and there is a service expectation of 100% availability and responsiveness. In addition, we have issues of large scale and 24 x 7 availability we can see that constructing such a service is a serious web engineering exercise.

If you are not monitoring the service, then you are just running software.

It’s never good when the first person to tell you that your service has a problem is one of your consumers. Without appropriate monitoring software this will inevitably be the case, and in all probability they won’t tell you immediately.

So, the first key differentiator between a service and a system is Monitoring.

Choose the right tools.

When our service was first constructed a very expensive piece of software was purchased to perform availability monitoring, however, Mr. Heisenberg was forgotten and the load associated with that particular tool was sufficient to detrimentally impact the system. The tool itself was sold as the usual universal panacea, however, in implementation it was clear that its forte was component monitoring and not service monitoring.

Running a live system with this tool gave us all sorts of problems. The tool required agents on all machines and was really only designed around component availability and even then this was often measured from the wrong place (inside the firewall).

We took a look at the open source offerings available at that time and selected two.

Event monitoring

Nagios has won lots of awards. We use it to monitor events from two locations.

  • Our DMZ where it looks at all of our components every 90 seconds and critically has thresholds set for Green, Amber and Red. While most components in our large system are duplicated to provide resilience, it’s absolutely vital to know when one of your resilient components has failed in order to prevent a systems failure.
  • The public Internet. From this location, we can look at the service(s) from the perspective of the end user.

Nagios is used to provide event monitoring. Implementing such a tool is not to be undertaken lightly. Getting the sensitivity correct so as not to cry wolf, and embedding the culture such that when an alert is sent out, the operational staff respond rapidly is, in my opinion, more difficult than installing the system in the first place.

Trend and volume monitoring

The second open source monitoring tool we use provides trend monitoring, After looking around we found Cacti .

While Nagios tells us when we have a specific issue/problem, Cacti provides us with the information to understand or diagnose the root cause. In measuring volumes and their trends, Cacti allows us to look across the whole application stack at any point in time and examine critical volumes.

Cacti is used to measure volumes. If a system can return a number, Cacti can capture, store and trend it. These volumes can be business or technical volumes examples of which might include the number of users logged into the system over time or critical system volumes such as bandwidth, disk space, CPU, or Memory usage.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
in a comparison of the stages of meiosis to the stage of mitosis, which stages are unique to meiosis and which stages have the same event in botg meiosis and mitosis
Leah Reply
Researchers demonstrated that the hippocampus functions in memory processing by creating lesions in the hippocampi of rats, which resulted in ________.
Mapo Reply
The formulation of new memories is sometimes called ________, and the process of bringing up old memories is called ________.
Mapo Reply
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Source:  OpenStax, The impact of open source software on education. OpenStax CNX. Mar 30, 2009 Download for free at http://cnx.org/content/col10431/1.7
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