An Administrator has determined that storage performance to a group of virtual machines is
reduced during peak activity. The VMs are all located in a VMFS datastore called Production1 on
an Active/Active storage array. The ESXi host running the VMs is currently configured with an
MRU multipathing policy.
Which of the following actions could be taken to improve the storage performance of these VMs
(Choose Two)?
A.
Change the storage multipathing policy to Round-Robin.
B.
Change the storage multipathing policy to Fixed.
C.
Add additional physical storage and add an extent to the VMFS datastore called Production1.
D.
Add additional physical storage, create a new VMFS datastore calledProduction2 on the new
storage,then migrate a portion of the VMs from Production1 to Production2.
Explanation:
Storage performance refers to how to how efficiently, (typically how quickly), storage
operates. By adding a new datastore, and migrate a portion of the virtual machines from
Production1 to Production2 is likely to reduce the load on the original datastore, and
hence improve responsiveness, and hence performance.These pathing policies can be used with VMware ESX 4.x:
Most Recently Used (MRU) Selects the first working path, discovered at system boot time. If this path becomes unavailable, the ESX host switches to an alternative path and continues to use the new path while it is available. This is the default policy for Logical Unit Numbers (LUNs) presented from an Active/Passive array. ESX does not return to the previous path when if, or when, it returns; it remains on the working path until it, for any reason, fails.
Note: The preferred flag, while sometimes visible, is not applicable to the MRU pathing policy and can be disregarded.
Fixed (Fixed) Uses the designated preferred path flag, if it has been configured. Otherwise, it uses the first working path discovered at system boot time. If the ESX host cannot use the preferred path or it becomes unavailable, ESX selects an alternative available path. The ESX host automatically returns to the previously-defined preferred path as soon as it becomes available again. This is the default policy for LUNs presented from an Active/Active storage array.
Round Robin (RR) Uses an automatic path selection rotating through all available paths, enabling the distribution of load across the configured paths.
For Active/Passive storage arrays, only the paths to the active controller will used in the Round Robin policy.
For Active/Active storage arrays, all paths will used in the Round Robin policy.Note: This policy is not currently supported for Logical Units that are part of a Microsoft Cluster Service (MSCS) virtual machine.
Fixed path with Array Preference The VMW_PSP_FIXED_AP policy was introduced in ESX 4.1. It works for both Active/Active and Active/Passive storage arrays that support ALUA. This policy queries the storage array for the preferred path based on the arrays preference. If no preferred path is specified by the user, the storage array selects the preferred path based on specific criteria.
Notes:These pathing policies apply to VMwares Native Multipathing (NMP) Path Selection Plugins (PSP). Third party PSPs have their own restrictions.
Switching to Round Robin from MRU or Fixed is safe and supported for all arrays unless otherwise explicitly documented.
Warning: VMware does not recommend changing the LUN policy from Fixed to MRU, as the automatic selection of the pathing policy is based on the array that has been detected by the NMP PSP.