Whether SaaS, IaaS or PaaS, one of the central concepts of all layers of
cloud computing is multi-tenancy. If there is no shared resource in a
deployment, it's difficult to justify calling that deployment "cloud."
Even NIST makes it more or less official within its formal definition of
cloud computing, which reads, in part:
Essential Characteristics: Resource pooling. The provider's computing
resources are pooled to serve multiple consumers using a multi-tenant model,
with different physical and virtual resources dynamically assigned and
reassigned according to consumer demand.
In most SaaS offerings, the multi-tenancy is manifold - the servers, the
application code, the database and even the individual tables or pages within
the database might be shared among different customers and users of the
In IaaS, multi-tenancy is implemented via virtualization tech... (more)
A leading cloud analyst recently told me that there are exactly two ways to
operate software: Software-as-a-Service (SaaS) and on-premises. He said,
"Either they run in the cloud and someone else takes full responsibility for
the underlying physical infrastructure and system management (SaaS); or they
run on your own equipment and you operate it yourself (on-prem)."
I said, "Not so fast."
To be sure, there are models where some of the administration is outsourced,
such as shared hosting or managed services. But these approaches still leave
the financial and management burden with... (more)
Think back to when you were a kid. Remember that thing you thought, felt,
wanted or did that you were embarrassed about? You probably worried that you
were the only person in the world who had that thought, feeling, desire or
behavior. It was your Little Secret. Only as you got older did you figure out
that it was actually pretty common, that everyone did that, or felt that way,
at least once in a while. And that maybe it even had a name.
If you're a nerd like me, you probably had more than one of these.
As we've talked to customers, prospects and vendors in the industry, we've
In an application deployed directly on IaaS, you know and control everything
about the database; in a SaaS application you know little and control
But how does it work in PaaS?
Since a PaaS is essentially a container that runs application code, and
virtually every application requires a persistent data store, most PaaS
offerings provide some kind of database services. Not surprisingly, Resource
PaaS offerings most closely resemble SaaS in that they hide more deployment
details, while Server PaaS offerings are more flexible but potentially more
complex. (For more on Res... (more)
Like an automobile, a web application needs occasional maintenance and
management over its life cycle. Although it doesn't need oil changes, it will
probably need version upgrades. There may not be manufacturer recalls, but
sometimes servers fail or hang. An application doesn't need to be washed and
detailed, but it does need to be backed up. And both cars and applications
need occasional performance tuning.
This article provides a complete list of the system management functions that
need to be performed on a standard architecture web application, with a
particular emphasis on ... (more)