Page 596 - Cloud computing: From paradigm to operation
P. 596

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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