Storage Troubleshooting

Question 1

List steps to verify storage configuration

Answer 1

Verify that the host’s storage adapters are listed on the HCL and used only as described in the HCL. ■ Verify that the storage systems used are listed on the HCL and are at the required firmware versions. ■ Verify that no configuration maximums have been exceeded. ■ Verify that no ESXi patches are required for the configuration. ■ Verify that SAN zoning and/or LUN masking are configured correctly. ■ Verify that the storage network (Fibre Channel or Ethernet) is connected and configured properly. ■ Verify that iSCSI or NFS systems are reachable via vmkping from all required ESXi hosts. ■ Verify that iSCSI targets have been configured. ■ Verify that iSCSI or NFS permissions are set up properly. ■ Verify that authentication to iSCSI systems works properly. ■ Verify that the chosen iSCSI adapter is configured properly. ■ Verify that jumbo frames are set up properly. ■ Verify the speed and duplex settings of network storage adapters. ■ Verify that datastores are accessible and/or mounted by all required ESXi hosts. ■ Verify that a supported path selection policy is being used. ■ Verify VMFS versions, volume sizes, and block sizes. ■ Verify that LUNs used for RDM are accessible.

Question 2

Study resxtop metrics

Answer 2

Question 3

Which esxtop metrics are helpful in determining IO latency on hba’s

Answer 3

CMDS/s, DAVG/cmd, KAVG/cmd

Question 4

Which esxtop Metrics are helpful in determining which VM is experiencing disk latency

Answer 4

CMDS/s, LAT/rd and LAT/wr

Question 5

What is the problem threshold for DAVG/cmd

Answer 5

A value greater than 20

Question 6

What is the problem threshold for KAVG/cmd

Answer 6

A value greater than 1 or 2 is considered high

Question 7

What is T10-Based Storage APIs - Array Integration and what version of vSphere was it first introduced in?

Answer 7

Allows virtual machines to be paused if the array runs out of space. Introduced in vSphere 4