applications, the variation can even approach up to
60%.
b) Different configurations: even in the
existence of the same hardware however, the way
this resource is configured plays a significant role in
its performance. The same applies for software
configurations (e.g. a DB instance over a virtual
cluster) or variations in the software development.
c) Multi-tenancy and obscure, black box
management by providers: Cloud infrastructures
deal with multiple different users that may start their
virtual resources on the same physical host at any
given time. However, the effect of concurrently
running VMs for example (Kousiouris et al., 2011)
significantly degrades the actual application
performance. This is even more affected by the
usage patterns of these resources by their virtual
owners or their clients. Furthermore, consolidation
decisions made by providers and that are unknown
to the users may group virtual resources on the same
physical node at any given time, without informing
the owner.
d) VM interference effects. In (Koh et al., 2007)
an interesting research investigates the performance
interference for a number of applications in
experimental virtual environments that were selected
for classifying their behaviour using different
metrics. The result from the research shows that
combined performance varies substantially with
different combinations of applications. Applications
that rarely interfere with each other achieve
performance to the standalone performance.
However, some combinations interfere with each
other in an adverse way. Furthermore, virtualization
is a technology used in all Cloud data centers to
ensure high utilization of hardware resources and
better manageability of VMs. Despite the advantages
provided by virtualization, they do not provide
effective performance isolation.
All these aspects plus the fact that Cloud
providers are separate entities and no information is
available on their internal structure and operation,
makes it necessary to macroscopically examine a
provider’s behaviour with regard to the offered
resources and on a series of metrics. This process
should be performed through benchmarking, by
using the suitable tools and tests. One of the key
aspects is that due to this dynamicity in resource
management, the benchmarking process must be
iterated over time, so that we can ensure as much as
possible that different hardware, different
management decisions (like e.g.
update/reconfiguration/improvement of the
infrastructure) are demonstrated in the refreshed
metric values, but also observe key characteristics
such as performance variation, standard deviation
etc. Finally, the acquired information should be
represented in a machine understandable way, in
order to be used in decision making systems.
The aim of this paper is to provide such
mechanisms to address the aforementioned issues. A
benchmarking framework designed in the context of
the FP7 ARTIST project is presented in order to
measure the ability of various Cloud offerings to a
wide range of applications, from graphics and
databases to web serving and streaming. The
framework has defined also a number of templates
in order to store this information in a machine
understandable fashion, so that it may be used by
service selection mechanisms. What is more. we
define a metric, namely Service Efficiency (SE), in
order to rank different services based on a
combination of performance, cost and workload
factors.
The paper is structured as follows. In Chapter 2,
an analysis of existing work is performed. In
Chapter 3 the description of the ARTIST tools for
mitigating these issues is presented, while in Chapter
4 a case study on AWS EC2 resources is presented.
Finally, conclusions and future work are contained
in Chapter 5.
2 RELATED WORK
Related work around this paper ranges in the fields
of performance frameworks, available benchmark
services and description frameworks and is based in
the according analysis performed in the context of
the ARTIST project (ARTIST Consortium D7.2,
2013). With regard to the former, the most relevant
to our work is (Garg, 2012). In this paper, a very
interesting and multi-level Cloud service comparison
framework is presented, including aspects such as
agility, availability, accountability, performance,
security and cost. Also an analytical hierarchical
process is described in order to achieve the optimal
tradeoff between the parameters. While more
advanced in the area of the combined metric
investigation, this work does not seem to include
also the mechanism to launch and perform the
measurements. Skymark (Iosup et al., 2012) is a
framework designed to analyze the performance of
IaaS environments. The framework consists of 2
components – Grenchmark and C-Meter.
Grenchmark is responsible for workload generation
and submission while C-Meter consists of a job
scheduler and submits the job to a Cloud manager
AMulti-CloudFrameworkforMeasuringandDescribingPerformanceAspectsofCloudServicesAcrossDifferent
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