1. What is the name of the software on the vCenter server normally responisble for moving data between arrays?

    A. VMKernal Data Mover
  2. If vCenter attempts to use hardware offload and the operation fails what happens?

    B. vCenter Server reverts to traditional software data movement.
  3. What changes were made in VAAI for vSphere 5.0?

    C. NAS and vSphere Thin Provisioning were added
  4. An application owner complains about storage performance. You check storage performance and sure enough there's a problem. Which of the following actions can you take that will resolve the problem?
    A. Use an array that supports ATS
    B. Use an array that supports ATS
    C. Add more LUNs
    D. Check your Queue Depth
    • A & C
    • C - No brainer
    • A - The Atomic Test & Set (ATS) primitive in VAAI replaces SCSI reservation locks that lock the entire LUN. ATS only modifies the disk sector on the VMFS volume.
  5. I've upgraded my VSphere 4.x to 5.x and am having storage performance problems. What can I do? 
    A. Use a VAAI-compliant Array
    B. Add another LUN
    C. Move your VMFS to it's own LUN
    D. Use a thick provisioned disk
    A, B, C, D

    Note that ATS-only flag is not provided on VMFS3 volumes upgraded to VMFS5, causing the use SCSI locks in some cases. ATS-only can be manually enabled.
  6. Which of the following tasks/issues can be accelerated by VAAI? (Select all that apply)
    A. Thick provisioning of disks
    B. Thin provisioning of disks
    C. VMotoin
    D. File locking
    E. Thick and Thin provisioning of disk
    • A, C, D
    • Expanding a thin provisioned disk is helped by VAAI, creating one is not.
  7. What does VAAI allow me to do with block storage?
    • A. Enhance locking (ATS)
    • B. Migrate or clone faster (XCOPY)
    • C. Create an EagerZeroed Thick Disk (WRITE SAME (ZERO))
  8. What does VAAI allow me to do with NAS storage?
    • 1. Clone virtual disks (Full File Clone)
    • 2. Offload snapshots (Fast File Clone)
    • 3. Better Statistics (Extended Statistics)
    • 4. Thick Provisioning (Reserve Space)
    • 5. Enhanced Thin Provisioning

    • I would like to accelerate Storage VMotion between my arrays. Which would of the following statement would most accurately describe if VAAI would help or not?
    • A. Yes
    • B. Yes, but only with block storage
    • C. Yes, but only with block and file storage
    • D. No.

    • B. Yes, but only with block storage
    • Full File Clone is the new primitive in VAAI that allows NAS devices to move clone storage. It cannot be used with storage vmotion.
  9. What VAAI primitive would allows me to offload the creation of VM snapshots onto the NAS array?

    B. Fast File Clone
  10. VAAI allows me greater visibility into my provisioned disks:

    E.  Extended Statistics enables visibility into space usage on NAS datastores. This is especially useful for thin-provisioned datastores because it enables vSphere to display actual space usage statistics in situations where oversubscription was used.
  11. With a conventional NAS datastore, what provisioning choices do I have?

  12. With VAAI NAS datastore, what provisioning choices do I have?
    A. Thick Provisioned Lazy Zeroed
    B. Thick Provisioned Eager Zeroed
    C. Thin Provisioned
    All of the above. Thick provisioning was added to NAS in VAAI 1.1
  13. If usage on a thin provisioned datastore reaches 100%, VAAI will:

    • B. Pause all VMs  requiring extra space
    • Thin Provisioning Stun - If a datastore reaches 100 percent usage, only those virtual machines requiring extra blocks of storage space are paused; those not needing additional space continue to run.
  14. What primitive indicates if a thin provisioned array reaches critical threshold?

    B. Space Threshold Warning
  15. VAAI will show an alarm if usage of a thin provisioned array exceeds a threshold. Where is the threshold specified?
    1. Defined on vCenter at Datastores -> Configuration -> Advanced options ->Array Options
    2. Defined on the Array 
    3. Defined on vCenter at host & cluster ->storage tab
    2. Threshold values are set on the array.
  16. User complain that after they delete their VMs, their arrays still report the same amount of consumed space. What command in VAAI would help with the problem?

    B. SCSI UNMAP is the command used by the Dead Space Reclamation primitive to enable a host to report to the array that storage can be reclaimed.
  17. Dead space reclamation is done automatically or not? 

    C. Yes for 5.0, no for 5.1
  18. What esxcli command would you use to show if hard acceleration is  supported by the device?

    A.  # esxcli storage core device vaai status get -d
  19. What esxcli command would you use to find out if your storage device supports VAAI at all?

    B. # esxcli storage core device list –d
  20. What variable indicates support for dead space reclamation in the esxcli?

    • B.  DELETE Status
    • a. Unmap is the SCSI command not the status
    • b. Zero is esxcli command above Delete status. I think it refers to being zero provisioned or not. 
    • c. Thinp is just bogus
  21. What ESXCLI command do we type to reclaim dead space on a volume?

    B. vmkfstools -y<% of free space>

    • - Unmap is the scsi command no the esxcli command
    • - delete is the variable that indicates an array can support dead space reclamation
    • - vmfstools is bogus
  22. What's the potential risk with deadspace reclamation?
    • If  "vmkfstools - y %XX" is spec for a % in high 90s or 100, the temporary balloon file might fill up the VMFS volume, preventing 
    • any growth of current VMDK files due to running virtual machines writing to their disks or the creation of new files, such as snapshots,.
  23. What command would you use to show the status of your thin-lun

    A.  lun show -v /vol/vol2/thin-lun
  24. I want to disable the deadspace  reclamantion threshold warning. What impact will disabling unmap have on my options?

    B. Nothing
  25. What is PSA and what was it's primary motivation?
    Pluggable Storage Architecture device filter frameworkenables VMware to introduce new value-add into the PSA stack asynchronously, decoupling it from the vSphere release cycle. The primary motivation is to support VAAI.
  26. If not for PSA, where would VAAI be implemented?
    In the Storage Array Type Policy (SATP) on a per array basis.
  27. What are the benefits of PSA?
    • - Reduces Duplicate Code
    • - Saves Memory Space in the VMKernal
    • - Enables 3rd party plug-ins to use offload primitives.
  28. What's the best way to explain A "device filter" in the PSA architectures?

    C. A way for vendors to insert value added software into PSA.
  29. What is a VAAI plug in?

    C. A way of implementing vendor-specific VAAI functions such as ATS, XCOPY and WRITE_SAME.
  30. What are the required components to VAAI?
    • The PSA device filter framework
    • VAAI plug-in specific to the VAAI device filter
  31. I want to purchase a new array, how can I know if it supports  VAAI?
    Any array that is T10 compliant should be able to use VAAI.
  32. My device is VAAI compliant, but it doesn't offer a PSA device filter. Is that a problem?
    No.VMware has a single PSA device filter plug-in called VAAI_FILTER. If a device supports VAAI offloads, it first will be claimed by the VAAI filter, VAAI_FILTER.
  33. What ESXcli command can I run to find out if my device has been claimed by a VAAI filter?
    # esxcli storage core device list -d
  34. What ESXCLI command can I run to find out if the VAAI plug-in has been installed?
    ~ # esxcli storage core plugin list
  35. What CLI command can be used to verify which vendor-specific VAAI plug-in has claimed a device and the primitives that it supports.
    ~ # esxcli storage core device vaai status get -d
  36. What is the default size used for hard accleration?
    The default size for XCOPY is 4MB and can be incremented to 16MB with the advice of the storage vendor.
  37. I'm using ESXTOP to manage my VAAI array and I see my average kernal latency is very high. What should be done?

    • C. Ignore the issue
    • One side effect of VAAI offloads is that it can lead to distorted kernal average latencies (KAVGs)
  38. Your shown the following output:
    ATS Status: supported
    Clone Status: supported
    Zero Status: Not supported
    Delete Status: Unknown
    What is the status of the following feature support for this array:
    A. Hard Acceleration
    B. Enhanced locking 
    C. Storage vMotion
    D. Eager Zeroed Thick Provisioning
    E. Lazy Zeroed Thick Provisioning
    F. Dead Space Reclamation
    • B. ATS: Enhanced locking support - YES
    • C. CLONE: Storage vMotion (XCOPY)  - YES
    • D. ZERO:  Eager Zeroed Thick Provisioning - NO
    • F. DELETE: Dead Space Reclamation- unknown

    • Note: 
    • A. Hard Acceleration is UNKNOWN. For Hard Acceleration to be supported,
    • a)ATS must be  supported
  39. Your shown the following output for your array
    ATS Status: unsupported
    Clone Status: SUPPORTED
    Zero Status: unsupported
    Delete Status: SUPPORTED
    What is the status of Hardware Acceleration?

    • C. Unknown. Hard acceleration status is as follows:
    • To be supported: ATS Status = supported
    • To be unsupported: ATS, CLONE, ZERO= unsupported
    • Any other combination equals Unknown
  40. I look at the state of my lun and I see that hardware acceleration is "Unknown." What can I do to determine if hardware acceleration is support/not?
    • Unknown is typically the state that is displayed until the first clone and zero operation is initiated. Many
    • users initiate an eagerzeroedthick clone of a file to test the VAAI status.
  41. What is degraded mode?
    A mode where the VAAI transfer FAILED and the VMkernal tries to accomplish the transfer using the software Data Mover.
  42. My array is in the middle of transferring a 500 GB file. It transfers 300 GB and then the VAAI transfer fails. How much data will have to be transferred when the host switches to Degraded Mode?
    200 GB . The transfer picks up from where the previous transfer left off. However, memory buffer requirements limit thee transfer size to 64KB (not 4MB of XCOPY)
  43. What are the differences between VAAI in vSphere 4.x and 5.x?
    • • Standard T10 primitives rather than per-array manufacturer commands.
    • • Full ATS support for all metadata operations with VMFS5.
    • • Support for NAS primitives, including VCAI.
    • • Suppor for Thin Provisioning primitives, including UNMAP.
    • • VMware HCL now requires performance of primitives before an array receives VAAI certification. This is important because certain storage arrays that appear in the vSphere 4.1 HCL might not appear in the vSphere 5.0 HCL if the performance of the offload primitives does not meet requirements.
  44. Hardware acceleration for NAS will allow faster provisioning and thick virtual disks through which two newly introduced VAAI primitives:

    A. Full File Clone enables virtual disks to be cloned by the NAS device rather than the Data Mover software in the host.

    D. Reserve Space allows creation of thick disks on a NAS file store
Card Set
Review of VAAI concepts