HA/DRS/vMotion Troubleshooting

Question 1

List the non-obvious requirements for HA

Answer 1

• All ESX/ESXi hosts must be licensed to use vSphere HA.
  ■ There must be at least two hosts in the cluster.
  ■ Static IP addresses or DHCP reservations are required for all hosts in the cluster.
  ■ A minimum of one common management network between the hosts in the cluster is
  required.
  ■ All hosts must have access to the same VM networks and shared storage.
  ■ All virtual machines in the cluster must be located on shared storage.
  ■ VMware Tools are required in virtual machines if VM Monitoring will be used.
  ■ Host certificate checking should be enabled.

Question 2

List the non-obvious requirements for a DRS cluster

Answer 2

• All hosts in the DRS cluster must be licensed to use DRS.
  ■ All hosts must have access to the same shared storage.
  ■ All virtual machines in the cluster must be located on shared storage.
  ■ Processor compatibilities should be maximized to most effectively use EVC.

Question 3

List the non-obvious requirements for vMotion and Storage vMotion

Answer 3

ESXi hosts must be licensed to use vMotion.
■ ESXi hosts must have VMkernel networking established for the vMotion traffic.
■ Virtual machines that use raw disks for clustering cannot be migrated.
Virtual machines that use a virtual device backed by a device that is not accessible on
the destination host cannot be migrated.
■ Virtual machines that use a virtual device backed by a device on the client computer
cannot be migrated.
■ Virtual machines that use USB pass-through devices can be migrated only if the devices
are enabled for vMotion.
The Storage vMotion requirements include the following:
■ ESXi hosts must be licensed to use Storage vMotion.
- Virtual Machine disks must be in persistent mode or be RDMs for Storage vMotion

Question 4

List steps to verify vMotion/Storage vMotion Configuration

Answer 4

• Verify the vSwitch/dvSwitch configuration on all ESX/ESXi source and target hosts.
  ■ If vSwitches are used, ensure that consistent network labels are used across all hosts in
  the cluster.
  ■ If dvSwitches are used, ensure that all hosts in the cluster are also members of all
  dvSwitches used by virtual machines.
  ■ Verify that a Gigabit Ethernet network connection exists between all hosts that will
  use vMotion/Storage vMotion.
  ■ A single Gigabit Ethernet interface should be dedicated to vMotion use.
  ■ Verify that the vMotion traffic is on an isolated network.
  ■ Verify that virtual machines have access to the same subnets on all ESXi hosts in the
  DRS cluster.
  ■ Verify that jumbo frames are configured from end to end properly, if applicable.

Question 5

List steps to verify HA network Configuration

Answer 5

• Verify that all hosts in the cluster have static IP addresses used for their management
  network(s).
  ■ Verify that the management network redundancy is present by using NIC Teaming or
  creating a second management network.
  Verify that the network isolation address can be pinged from the ESXi Shell. The network
  isolation address is the default gateway, unless it has been manually modified.
  ■ Verify that the upstream physical network switches support Spanning-Tree PortFast or
  an equivalent setting.
  ■ Verify that consistent port group names and network labels are used on all virtual
  switches.
  ■ Verify that the entire configuration is fully documented.

Question 6

What is the best way to test HA configuration

Answer 6

Fail the management network connection

Question 7

List five constraints that affect DRS imbalances

Answer 7

- Memory contention
■ CPU contention
■ ESXi hosts in maintenance mode
■ VM-Host affinity/anti-affinity rules
■ VM-VM affinity rules

Question 8

What is the invocation period for DRS?

Answer 8

300 seconds

Question 9

What is the cause of a DRS host load standard deviation value of N/A

Answer 9

The migration threshold is set to conservative

Question 10

List the steps to troubleshoot vMotion/Storage vMotion Issues

Answer 10

Ensure that all hosts are licensed for vMotion and/or Storage vMotion.
■ Verify EVC and/or the processor compatibility of the hosts in the cluster.
Ensure that vMotion networking exists on all hosts in the cluster.
■ If vSwitches are used, ensure that consistent network labels are used across all hosts in
the cluster.
■ If dvSwitches are used, ensure that all hosts in the cluster are also members of all
dvSwitches used by virtual machines.
■ Use vmkping to verify network connectivity of the vMotion VMkernel interface for all
hosts in the cluster.
■ Verify that no firewalls are between hosts in the cluster.
■ Verify virtual switch settings, including VLAN and MTU.
■ Verify that time is synchronized across all hosts in the cluster.
■ Verify that virtual machines aren’t attached to devices on the local ESXi hosts.
■ Ensure that the virtual machine is not in the middle of a VMware Tools installation.
■ Verify required disk space is available in datastores when using Storage vMotion.
■ Verify that all hosts in the cluster have access to the same shared storage.