Section 8 – Perform Basic Troubleshooting and Alarm Management
- Objective 8.4 – Perform Basic Troubleshooting for Storage
An administrator is configuring software iSCSI multipathing. Which of the following is the minimum required configuration for Round Robin multipathing?
A.Configure 2 VMkernel ports. Bind each port to a different uplink on the same virtual switch. Choose the Round Robin Path Selection Plugin (PSP)
B.Configure 2 VMkernel ports. Connect each port to a unique virtual switch with uplinks on separate subnets. Choose the Round Robin Path Selection Plugin (PSP)
C.Configure 1 VMkernel port. Bind the port to multiple uplinks on the same virtual switch. Choose the Round Robin Path Selection Plugin (PSP)
D.Configure 1 VMkernel port. Connect the port to a switch with multiple uplinks. Choose the Round Robin Path Selection Plugin (PSP)
A "Multivendor Post" on using iSCSI with VMware vSphere
So – setup in 4 easy steps:
Step 1 – configure multiple vmkNICs
Ok, the first obvious (but we’re not making any assumptions) is that you will need to configure multiple physical Ethernet interfaces, and multiple vmkernel NIC (vmkNIC) ports.
Step 2 – configure explicit vmkNIC-to-vmNIC binding.
To make sure the vmkNICs used by the iSCSI initiator are actual paths to storage, ESX configuration requires the vmkNIC is connected to a portgroup that only has one active uplink and no standby uplinks. This way, if the uplink is unavailable, the storage path is down and the storage multipathing code can choose a different path.
Step 3 – configuring the iSCSI initiator to use the multiple vmkNICs
Then the final step requires command line configuration. This step is where you assign, or bind, the vmkNICs to the ESX iSCSI initiator. Once the vmkNICs are assigned, the iSCSI initiator uses these specific vmkNICs as outbound ports, rather than the vmkernel routing table.
Step 4 – Enabling Multipathing via the Pluggable Storage Architecture VMware ships with a set of native SATPs, and 3 PSPs: Fixed, Most Recently Used (MRU), & Round Robin (RR). Fixed and MRU options were available in VI3.x and should be familiar to readers. Round Robin was experimental in VI3.5, and is supported for production use in vSphere (all versions) Configuring NMP to use a specific PSP (such as Round Robin) is simple and easy. You can do it in the vSphere Client under configuration, storage adapter, select the devices, and right click for properties.
Which of the following are default displayed fields when viewing a report for a VMFS Datastore in the Storage Views tab (Choose Two)?
B.Multipathing Redundancy for VM
D.Virtual Disk Space
An administrator is updating a program running on a virtual machine. The update file has been downloaded as an .iso file and placed on a shared NFS datastore. An attempt to mount the .iso to the virtual machine fails, but subsequent testing shows that the .iso can be mounted to a VM running on another ESX Host. Which of the following steps should be taken to enable access to the .iso for the affected VM?
A.Remount the NFS volume to the ESX server running the affected VM
B.Rescan all datastores
C.Reboot the ESX Server running the affected VM
D.Reboot the NFS Server
Which of the following types of datastores can be unmounted? (Choose Two)?
A.Only NFS datastores configured as Read Only
B.VMFS datastore copies mounted with resignaturing
C.VMFS datastore copies mounted without resignaturing
D.Any NFS datastore
What is the maximum number of LUNs that can be assigned per ESX Host?
Configuration Maximums VMware® vSphere 4.0 and vSphere 4.0 Update 1, page 4.
Table 2. Storage Maximums
* LUNs per host 256
Which of these factors indicates a high likelihood that the performance of a virtual machine is being constrained by disk I/O?
A.A large number of kilobytes read and written
B.A large number of virtual disks on its SCSI bus
C.A large number of disk shares
D.A long SCSI queue length
When you delete a VMFS datastore from an ESX Host, which of the following occurs?
A.all hosts that were configured to use the datastore will no longer see the datastore, but it will remain on the storage device and can be remounted as needed
B.only hosts in the same DRS/HA cluster no longer see the datastore, but it will remain on the storage device and can be remounted as needed
C.all hosts that were configured to use the datastore will no longer see the datastore and it is deleted from the storage device
D.the datastore will no longer be available to the host that it was deleted from, but all other hosts that were configured to use the datastore will remain connected
An administrator is reporting slow access to datastores from multiple ESX Hosts. The datastores are all FC SAN on ESX 3.x and ESX 4 Hosts. Which of the following two actions can be taken to improve performance (Choose Two)?
A.Unload the LUN Masking driver using the vmkload_mod -u qla2300
B.Unload the FSAUX driver using the vmkload_mod -u fsaux
C.Unload the NFS driver using the vmkload_mod -u nfsclient
D.Unload the VMFS-2 driver using the vmkload_mod -u vmfs2
Which of these factors indicates a high likelihood that a virtual machine’s performance is being constrained by disk I/O?
A.A long SCSI queue length
B.A large number of virtual disks on its SCSI bus
C.A large number of kilobytes read and written
D.A large number of disk shares
What are the three possible storage multi-pathing policies that you can set in ESX Server? (Choose Three.)
B.Most Recently Used (MRU)
C.Open Shortest Path First (OSPF)
Fibre Channel SAN Configuration Guide ESX 4.0 ESXi 4.0 vCenter Server 4.0, page 62.
By default, VMware supports the following path selection policies. If you have a third-party PSP installed on your host, its policy also appears on the list.
1. Fixed (VMware) The host always uses the preferred path to the disk when that path is available. If the host cannot access the disk through the preferred path, it tries the alternative paths. The default policy for active-active storage devices is Fixed.
2. Most Recently Used (VMware) The host uses a path to the disk until the path becomes unavailable. When the path becomes unavailable, the host selects one of the alternative paths. The host does not revert back to the original path when that path becomes available again. There is no preferred path setting with the MRU policy. MRU is the default policy for active-passive storage devices and is required for those devices.
3. Round Robin (VMware) The host uses an automatic path selection algorithm rotating through all available paths. This implements load balancing across all the available physical paths. Load balancing is the process of spreading server I/O requests across all available host paths. The goal is to optimize performance in terms of throughput (I/O per second, megabytes per second, or response times).