02 Février, 2010 11:16
VCP-410 Real Exam Questions
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Periodically (every two seconds by default), the system examines the loads of the various nodes and determines if it should rebalance the load
by moving a virtual machine from one node to another.
o Transparent page sharing has also been optimized for use on NUMA systems.
o The VMkernel.Boot.sharePerNode option controls whether memory pages can be shared (de-duplicated) only within a sVCP-410 ingle NUMA node or
across multiple NUMA nodes. It is turned on by default.
o If you turn off the option, identical pages can be shared across different NUMA nodes. In memory-constrained environments, such as VMware
View this could be very beneficial.
o The systems that offer a NUMA platform include AMD CPUs or the IBM Enterprise X-Architecture.
o You must manually select the boxes for all processors in the NUMA node. CPU affinity is specified on a per-processor, not on a per-node, basis.
o Specify nodes to be used for future memory allocations only if you have also specified CPU affinity.
Appendix A - Performance Monitoring Utilities: resxtop and esxtop
o The esxtop utility reads its default configuration from .esxtop4rc.
o Do not edit the .esxtop4rc file. Instead, select the fields and the order in a running esxtop process, make changes, and save this file using
the W interactive command.
Appendix B – Advanced attributes
vSphere Availability Guide
o The first five hosts added to the cluster are designated as primary hosts, and all subsequent hosts are designated as secondary hosts. The
primary hosts maintain and replicate all cluster state and are used to initiate failover actions. If a primary host is removed from the cluster,
VMware HA promotes another host to primary status.
o One of the primary hosts is also designated as the active primary host and its responsibilities include:
o Deciding where to restart virtual machines.
o Keeping track of failed restart attempts.
o Determining when it is appropriate to keep trying to restart a virtual machine.
o If the active primary host fails, another primary host replaces it.
o If a host stops receiving heartbeats from all other hosts in the cluster for more than 12 seconds, it attempts to ping its isolation addresses. If
this also fails, the host declares itself as isolated from the network.
o Three types of admission control:
o Host
o Resource pool
o HA
o Only VMware HA admission control can be disabled.
o Slot size is a logical representation of t VCP-410 braindump he memory and CPU resources that satisfy the requirements for any powered-on virtual machine in the
cluster.
o The maximum Configured Failover Capacity that you can set is four.
o If your cluster contains any virtual machines that have much larger reservations than the others, they will distort slot size calculation. To avoid
this, you can specify an upper bound for the CPU or memory component of the slot size by using the das.slotCpuInMHz or das.slotMemInMB
advanced attributes, respectively.
o You can configure VMware HA to perform admission control by reserving a specific percentage of cluster resources for recovery from host
failures.
o You can configure VMware HA to designate a specific host as the failover host.
o To ensure that spare capacity is available on the failover host, you are prevented from powering on virtual machines or using VMotion to
migrate virtual machines to the failover host.
o When choosing an admission control policy, you should consider a number of factors:
o Avoiding Resource Fragmentation - The Host Failures Cluster Tolerates policy avoids resource fragmentation by defining a slot as the
maximum virtual machine reservation. The Percentage of Cluster Resources policy does not address the problem of resource
fragmentation. With the Specify a Failover Host policy, resources are not fragmented because a single host is reserved for failover.
o Flexibility of Failover Resource Reservation - The Host Failures Cluster Tolerates policy allows you to set the failover level from one to four
hosts. The Percentage of Cluster Resources policy allows you to designate up to 50% of cluster resources for failovVCP-410 exam er. The Specify a
Failover Host policy only allows you to specify a single failover host.
o Heterogeneity of Cluster - In a heterogeneous cluster, the Host Failures Cluster Tolerates policy can be too conservative because it only
considers the largest virtual machine reservations when defining slot size and assumes the largest hosts fail when computing the Current
Failover Capacity. The other two admission control policies are not affected by cluster heterogeneity
by moving a virtual machine from one node to another.
o Transparent page sharing has also been optimized for use on NUMA systems.
o The VMkernel.Boot.sharePerNode option controls whether memory pages can be shared (de-duplicated) only within a sVCP-410 ingle NUMA node or
across multiple NUMA nodes. It is turned on by default.
o If you turn off the option, identical pages can be shared across different NUMA nodes. In memory-constrained environments, such as VMware
View this could be very beneficial.
o The systems that offer a NUMA platform include AMD CPUs or the IBM Enterprise X-Architecture.
o You must manually select the boxes for all processors in the NUMA node. CPU affinity is specified on a per-processor, not on a per-node, basis.
o Specify nodes to be used for future memory allocations only if you have also specified CPU affinity.
Appendix A - Performance Monitoring Utilities: resxtop and esxtop
o The esxtop utility reads its default configuration from .esxtop4rc.
o Do not edit the .esxtop4rc file. Instead, select the fields and the order in a running esxtop process, make changes, and save this file using
the W interactive command.
Appendix B – Advanced attributes
vSphere Availability Guide
o The first five hosts added to the cluster are designated as primary hosts, and all subsequent hosts are designated as secondary hosts. The
primary hosts maintain and replicate all cluster state and are used to initiate failover actions. If a primary host is removed from the cluster,
VMware HA promotes another host to primary status.
o One of the primary hosts is also designated as the active primary host and its responsibilities include:
o Deciding where to restart virtual machines.
o Keeping track of failed restart attempts.
o Determining when it is appropriate to keep trying to restart a virtual machine.
o If the active primary host fails, another primary host replaces it.
o If a host stops receiving heartbeats from all other hosts in the cluster for more than 12 seconds, it attempts to ping its isolation addresses. If
this also fails, the host declares itself as isolated from the network.
o Three types of admission control:
o Host
o Resource pool
o HA
o Only VMware HA admission control can be disabled.
o Slot size is a logical representation of t VCP-410 braindump he memory and CPU resources that satisfy the requirements for any powered-on virtual machine in the
cluster.
o The maximum Configured Failover Capacity that you can set is four.
o If your cluster contains any virtual machines that have much larger reservations than the others, they will distort slot size calculation. To avoid
this, you can specify an upper bound for the CPU or memory component of the slot size by using the das.slotCpuInMHz or das.slotMemInMB
advanced attributes, respectively.
o You can configure VMware HA to perform admission control by reserving a specific percentage of cluster resources for recovery from host
failures.
o You can configure VMware HA to designate a specific host as the failover host.
o To ensure that spare capacity is available on the failover host, you are prevented from powering on virtual machines or using VMotion to
migrate virtual machines to the failover host.
o When choosing an admission control policy, you should consider a number of factors:
o Avoiding Resource Fragmentation - The Host Failures Cluster Tolerates policy avoids resource fragmentation by defining a slot as the
maximum virtual machine reservation. The Percentage of Cluster Resources policy does not address the problem of resource
fragmentation. With the Specify a Failover Host policy, resources are not fragmented because a single host is reserved for failover.
o Flexibility of Failover Resource Reservation - The Host Failures Cluster Tolerates policy allows you to set the failover level from one to four
hosts. The Percentage of Cluster Resources policy allows you to designate up to 50% of cluster resources for failovVCP-410 exam er. The Specify a
Failover Host policy only allows you to specify a single failover host.
o Heterogeneity of Cluster - In a heterogeneous cluster, the Host Failures Cluster Tolerates policy can be too conservative because it only
considers the largest virtual machine reservations when defining slot size and assumes the largest hosts fail when computing the Current
Failover Capacity. The other two admission control policies are not affected by cluster heterogeneity
