An Administrator has determined that storage performance to a group of virtual machines is reduced during peak activity. The virtual machines are all located in a VMFS datastore called Production I on an Active/Active storage array. The ESX Host is currently configured with an MRU multipathing policy.
Which of the following achons could be taken to improve the storage performance of these virtual machines (Choose Two)?
A.
Add additional physical storage and add an extent to the VMFS datastore called Productionl
B.
Change the storage multipathing policy to Fixed
C.
Change the storage multipathing policy to Round-Robin
D.
Add additional physical storage, create a new VMFS datastore called Production2 on the new storage, then migrate a portion of the virtual machines from Production I to Production 2
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 VMware’s 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.
Hell Admin,
I found two diiferent answers for this question. According to below link option D and C is correct. can you please explain how option B will help here?
http://www.aiotestking.com/vmware/2011/12/which-two-actions-can-be-taken-to-improve-the-storage-performance-of-these-virtual-machines/comment-page-1/#comment-1310
Hello Admin,
I found two diiferent answers for this question. According to below link option D and C is correct. can you please explain how option B will help here?
http://www.aiotestking.com/vmware/2011/12/which-two-actions-can-be-taken-to-improve-the-storage-performance-of-these-virtual-machines/comment-page-1/#comment-1310
Plz Reply
Please read carefully the explanation.
“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.”
C is correct.
For Active/Active storage arrays, all paths will used in the Round Robin policy.
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1011340
Fixed won’t improve the storage performance.