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as well as identify and prevent or minimize the impact of incidents that may occur. Pinpointing the root cause of an incident can become more challenging when workloads are abstracted |
from the infrastructure and their physical location changes frequently. Additionally, incident response teams may be unfamiliar with virtualization technologies (at least initially) which could also lead to delays in incident |
resolution. Finally, applications may have neither a robust Health Model nor expose all of the health information required for a proactive response. All of this may lead to an increase |
in reactive (user initiated) incidents which will likely increase the Mean-Time-to-Restore-Service (MTRS) and customer dissatisfaction. This may seem to go against the resiliency principle, but note that virtualization alone will |
not achieve the desired resiliency unless accompanied by highly mature IT Service Management (ITSM) maturity and a robust automated health monitoring system. The drive for resiliency requires a different approach |
to troubleshooting incidents. Extensive troubleshooting of incidents in production negatively impacts resiliency. Therefore, if an incident cannot be quickly resolved, the service can be rolled back to the previous version, |
as described under Release and Deployment. Further troubleshooting can be done in a test environment without impacting the production environment. Troubleshooting in the production environment may be limited to moving |
the service to different hosts (ruling out infrastructure as the cause) and rebooting the VMs. If these steps do not resolve the issue, the rollback scenario could be initiated. Minimizing |
human involvement in incident management is critical for achieving resiliency. The troubleshooting scenarios described earlier could be automated, which will allow for identification and possible resolution of the root much |
more quickly than non-automated processes. But automation may mask the root cause of the incident. Careful consideration should be given to determining which troubleshooting steps should be automated and which |
require human analysis. Human Analysis of Troubleshooting If a compute resource fails, it is no longer necessary to treat the failure as an incident that must be fixed immediately. It |
may be more efficient and cost effective to treat the failure as part of the decay of the Resource Pool. Rather than treat a failed server as an incident that |
requires immediate resolution, treat it as a natural candidate for replacement on a regular maintenance schedule, or when the Resource Pool reaches a certain threshold of decay. Each organization must |
balance cost, efficiency, and risk as it determines an acceptable decay threshold – and choose among these courses of action: The benefits and trade-off of each of the options are |
listed below: Option 4 is the least desirable, as it does not take advantage of the resiliency and cost reduction benefits of a private cloud. A well-planned Resource Pool and |
Reserve Capacity strategy will account for Resource Decay. Option 1 is the most recommended approach. A predictable maintenance schedule allows for better procurement planning and can help avoid conflicts with |
other maintenance activities, such as software upgrades. Again, a well-planned Resource Pool and Reserve Capacity strategy will account for Resource Decay and minimize the risk of exceeding critical thresholds before |
the scheduled maintenance. Option 3 will likely be the only option for self-contained Scale Unit scenarios, as the container must be replaced as a single Scale Unit when the decay |
threshold is reached. The goal of Request Fulfillment is to manage requests for service from users. Users should have a clear understanding of the process they need to initiate to |
request service and IT should have a consistent approach for managing these requests. Much like any service provider, IT should clearly define the types of requests available to users in |
the service catalog. The service catalog should include an SLA on when the request will be completed, as well as the cost of fulfilling the request, if any. The types |
of requests available and their associated costs should reflect the actual cost of completing the request and this cost should be easily understood. For example, if a user requests an |
additional VM, its daily cost should be noted on the request form, which should also be exposed to the organization or person responsible for paying the bill. It is relatively |
easy to see the need for adding resources, but more difficult to see when a resource is no longer needed. A process for identifying and removing unused VMs should be |
put into place. There are a number of strategies to do this, depending on the needs of a given organization, such as: The benefits and trade-offs of each of these |
approaches are detailed below: Option 4 affords the greatest flexibility, while still working to minimize server sprawl. When a user requests a VM, they have the option of setting an |
expiration date with no reminder (for example, if they know they will only be using the workload for one week). They could set an expiration deadline with a reminder (for |
example, a reminder that the VM will expire after 90 days unless they wish to renew). Lastly, the user may request no expiration date if they expect the workload will |
always be needed. If the last option is chosen, it is likely that underutilized VMs will still be monitored and owners notified. Finally, self-provisioning should be considered, if appropriate, when |
evaluating request fulfillment options to drive towards minimal human involvement. Self-provisioning allows great agility and user empowerment, but it can also introduce risks depending on the nature of the environment |
in which these VMs are introduced. For an enterprise organization, the risk of bypassing formal build, stabilize, and deploy processes may or may not outweigh the agility benefits gained from |
the self-provisioning option. Without strong governance to make sure each VM has an end-of-life strategy, the fabric may become congested with VM server sprawl. The pros and cons of self-provisioning |
options are listed in the next diagram: The primary decision point for determining whether to use self-provisioning is the nature of the environment. Allowing developers to self-provision into the development |
environment greatly facilitates agile development, and allows the enterprise to maintain release management controls as these workloads are moved out of development and into test and production environments. A user-led |
community environment isolated from enterprise mission-critical applications may also be a good candidate for self-provisioning. As long as user actions are isolated and cannot impact mission critical applications, the agility |
and user empowerment may justify the risk of giving up control of release management. Again, it is essential that in such a scenario, expiration timers are included to prevent server |
sprawl. The goal of Access Management is to make sure authorized users have access to the services they need while preventing access by unauthorized users. Access Management is the implementation |
of security policies defined by Information Security Management at the Service Delivery Layer. Maintaining access for authorized users is critical for achieving the perception of continuous availability. Besides allowing access, |
Access Management defines users who are allowed to use, configure, or administer objects in the Management Layer. From a provider’s perspective, it answers questions like: From a consumer’s perspective, it |
answers questions such as: Access Management is implemented at several levels and can include physical barriers to systems such as requiring access smartcards at the data center, or virtual barriers |
such as network and Virtual Local Area Network (VLAN) separation, firewalling, and access to storage and applications. Taking a service provider’s approach to Access Management will also make sure that |
resource segmentation and multi-tenancy is addressed. Resource Pools may need to be segmented to address security concerns around confidentiality, integrity, and availability. Some tenants may not wish to share infrastructure |
resources to keep their environment isolated from others. Access Management of shared infrastructure requires logical access control mechanisms such as encryption, access control rights, user groupings, and permissions. Dedicated infrastructure |
also relies on physical access control mechanisms, where infrastructure is not physically connected, but is effectively isolated through a firewall or other mechanisms. The goal of systems administration is to |
make sure that the daily, weekly, monthly, and as-needed tasks required to keep a system healthy are being performed. Regularly performing ongoing systems administration tasks is critical for achieving predictability. |
As the organization matures and the Knowledge Management database becomes more robust and increasingly automated, systems administration tasks is no longer part of the job role function. It is important |
to keep this in mind as an organization moves to a private cloud. Staff once responsible for systems administration should refocus on automation and scripting skills – and on monitoring |
Let and be two differentiable functions. We will say that and are proportional if and only if there exists a constant C such that . Clearly any function is proportional |
to the zero-function. If the constant C is not important in nature and we are only interested into the proportionality of the two functions, then we would like to come |
up with an equivalent criteria. The following statements are equivalent: Therefore, we have the following: Define the Wronskian of and to be , that is The following formula is very |
useful (see reduction of order technique): Remark: Proportionality of two functions is equivalent to their linear dependence. Following the above discussion, we may use the Wronskian to determine the dependence |
Published May 2008 Properly located digital signage in high traffic areas on school campuses provides students and faculty with a convenient resource to stay up to date about the latest |
school news and activities. Signage in Education By Anthony D. Coppedge Technology gets high marks. Digital media and communications have come to play a vital role in people’s everyday lives, |
and a visit to the local K-12 school, college or university campus quickly illustrates the many ways in which individuals rely on audio and visual technologies each day. The shift |
from analog media to digital, represented by milestones ranging from the replacement of the Walkman by the MP3 player to the DTV transition currently enabling broadcasts beyond the home to |
mobile devices, has redefined the options that larger institutions, including those in our educational system, have for sharing information across the campus and facilities. Flexible And Efficient Digital signage, in |
particular, is proving to be a flexible and efficient tool for delivering specific and up-to-date information within the educational environment. As a high-resolution, high-impact medium, it lives up to the |
now-widespread expectation that visual media be crisp and clear, displayed on a large screen. Although the appeal of implementing digital signage networks does stem, in part, from plummeting screen prices |
and sophisticated content delivery systems, what’s equally or more important is that digital signage provides valuable information to the people who need it, when and where they need it. On |
school campuses—whether preschool, elementary, high school or post-secondary institutions—it does so effectively, for both educational purposes and for the security and safety of staff, administration and the student body as |
a whole. School campuses have begun leveraging digital signage technology in addition to, or in place of, printed material, such as course schedules, content and location; time-sensitive school news and |
updates; maps and directions; welcome messages for visitors and applicants; and event schedules. Digital signage simplifies creation and delivery of multiple channels of targeted content to different displays on the |
network. Although a display in the college admissions office might provide prospective students with a glimpse into student life, for example, another display outside a lab or seminar room might |
present the courses or lectures scheduled for that space throughout the day. This model of a distribution concept illustrates a school distributing educational content over a public TV broadcast network. |
At the K-12 level, digital signage makes it easy to deliver information such as team or band practice schedules, or to post the cafeteria menu and give students information encouraging |
sound food choices. Digital signage in the preschool and daycare setting makes it easy for teachers and caregivers to share targeted educational programming with their classes. Among the most striking |
benefits of communicating through digital signage is the quality of the pictures and the flexibility with which images, text and video can be combined in one or more windows to |
convey information. Studies have shown that dynamic signage is noticed significantly more often than are static displays and, furthermore, that viewers are more likely to remember that dynamic content. Though |
most regularly updated digital signage content tends to be text-based, digital signage networks also have the capacity to enable the live campus-wide broadcast of key events: a speech by a |
visiting dignitary, the basketball team’s first trip to the state or national tournament, or even the proceedings at commencement and graduation. When time is short, it’s impractical to gather the |
entire student body in one place or there simply isn’t the time or means to deliver the live message in any other way. The ability to share critical information to |
the entire school community, clearly and without delay, has made digital signage valuable as a tool for emergency response and communications. Parents, administrators, teachers and students today can’t help but |
be concerned about the school’s ability to respond quickly and effectively to a dangerous situation, whether the threat be from another person, an environmental hazard, an unpredictable weather system or |
some other menace. Digital signage screens installed across a school campus can be updated immediately to warn students and staff of the danger, and to provide unambiguous instructions for seeking |
shelter or safety: where to go and what to do. Although early digital signage systems relied on IP-based networks and point-to-point connections between a player and each display, current solutions |
operate on far less costly and much more scalable platforms. Broadcast-based digital signage models allow content to be distributed remotely from a single data source via transport media, such as |
digital television broadcast, satellite, broadband and WiMAX. The staff member responsible for maintaining the digital signage network can use popular content creation toolsets to populate both dynamic and static displays. |
This content is uploaded to a server that, in turn, feeds the digital signage network via broadcast, much like datacasting, to the receive site for playout. By slotting specific content |
into predefined display templates, each section with its own playlist, the administrator can schedule display of multiple elements simultaneously or a single-window static, video or animated display. The playlist enables |
delivery of the correct elements to the targeted display both at the scheduled time and in the appropriate layout. In networks with multicast-enabled routers, the administrator can schedule unique content |
for displays in different locations. In the case of delivering emergency preparedness or response information across a campus, content can be created through the same back-office software used for day-to-day |
digital signage displays. Within the broadcast-based model, three components ensure the smooth delivery of content to each display. A transmission component serves as a content hub, allocating bandwidth and inserting |
content into the broadcast stream based on the schedule dictated by the network’s content management component. Content is encapsulated into IP packets that, in turn, are encapsulated into MPEG2 packets |
for delivery. Generic content distribution model for digital signage solution. The content management component of the digital signage network provides for organization and scheduling of content, as well as targeting |
of that content to specific receivers. Flexibility in managing the digital signage system enables distribution of the same emergency message across all receivers and associated displays, or the delivery of |
select messages to particular displays within the larger network. With tight control over the message being distributed, school administrators can immediately provide the information that students and staff in different |
parts of the campus need to maintain the safest possible environment. Receivers can be set to confirm receipt of content, in turn assuring administrative and emergency personnel that their communications |
are, in fact, being conveyed as intended. On the receiving end, the third component of the system, content, is extracted from the digital broadcast stream and fed to the display |
screen. The relationships that many colleges and universities share with public TV stations provide an excellent opportunity for establishing a digital signage network. Today, the deployed base of broadcast-based content |
distribution systems in public TV stations is capable of reaching 50% of the US population. These stations’ DTV bandwidth is used not only for television programming, but also to generate |
new revenues and aggressively support public charters by providing efficient delivery of multimedia content for education, homeland security and other public services. Educational institutions affiliated with such broadcasters already have |
the technology, and much of the necessary infrastructure, in place to launch a digital signage network. In taking advantage of the public broadcaster’s content delivery system, the college or university |
also can tap into the station’s existing links with area emergency response agencies. As digital signage technology continues to evolve, educational institutions will be able to extend both urgent alerts |
and more mundane daily communications over text and email messaging. Smart content distribution systems will push consistent information to screens of all sizes, providing messages not only to displays, but |
also to the cell phones and PDAs so ubiquitous in US schools. The continued evolution of MPH technology will support this enhancement in delivery of messages directly to each student. |
MPH in-band mobile DTV technology leverages ATSC DTV broadcasts to enable extensions of digital signage and broadcast content directly to personal devices, whether stationary or on the move. Rather than |
rely on numerous unrelated systems, such as ringing bells, written memos and intercom announcements, schools can unify messaging and its delivery, in turn reducing the redundancy involved in maintaining communications |
with the student body. An effective digital signage network provides day-to-day benefits for an elementary school, high school, college or university while providing invaluable emergency communications capabilities that increasingly are |
considered a necessity, irrespective of whether they get put to the test. The selection of an appropriate digital signage model depends, of course, on the needs of the organization. Educational |
institutions share many of the same concerns held by counterparts in the corporate world, and key among those concerns is the simple matter of getting long-term value and use out |
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