Page 596 - Cloud computing: From paradigm to operation

3 XaaS

– gathers information on the platform power consumption or utilization according to the weighted
resource usage from the power management function (see clause 7.3.6);
NOTE 7 – The weighted resource usage mean which resources are heavily used as usual; the platform power
consumption is estimated by the sum of these usages.
– performs the scheduling from the policies about a DaaS user's usage pattern and power
consumption in virtualization infrastructure;

– sends a policy to the allocation function (see clause 7.2.4) to select the virtualization infrastructure
to operate a virtual desktop;
– establishes a backup policy which covers types and frequency of backing up the virtual desktop
enviorment to prepare for a system disaster;
– provides user interfaces for established policies which are established and applied dynamically or
manually by the administrator.

7.3.5 High availability for DaaS
For high availability, DaaS adopts platform clustering which includes connection manger and virtualization
infrastructure to maintain the seamless DaaS user's connection in a failure occurrence situation. The high
availability for DaaS function:

– detects a system failure by confirming states among DaaS platforms;
– ensures DaaS users have a stable running environment in terms of delivery and operation of virtual
desktops;

– sets up the redundancy for the client connection management function (see clause 7.2.2) to perform
failover with minimum downtime and connection continuity;
NOTE 1 – The redundancy for the client connection management function (see clause 7.2.2) includes the
duplication by active-active form or active-standby form. In order not to lose the DaaS user's connection, CSU's
account and access information (such as DB, license or active directory) are duplicated or mirrored.
– configures the failover to redundancy for virtualization infrastructure;
NOTE 2 – The redundancy for virtualization infrastructure (such as the redundant server on active state for
virtual desktop environments) is configured to perform failover for minimizing downtime. It helps to allocate
a virtual desktop by load balancing or migrating a virtual desktop to the activated server to a DaaS client when
the failure occurs on the server to which the virtual desktop is allocated, by providing a service without the
loss of the user environment.
– saves the user's environment during a certain time and backs up and restores it on a local disk or on
shared storage, thus preventing the loss of the user environment.
7.3.6 Power management of virtual desktop resource

The power management of virtual desktop resources function manages the power consumption of a DaaS
platform with virtual desktop resources. This function:

– monitors the power consumption and the related performance factors of a virtual desktop and each
resource in a DaaS platform;
– calculates the variation of power consumption and performance of a virtual desktop or a DaaS
platform by collecting monitoring information;
– supports other functions for the provisioning and allocation of virtual desktop function
(see clause 7.2.4) or the operational policy management for DaaS function (see clause 7.3.4).

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