EMC EMC Certifications E20-526 Questions & Answers

• Question 51:

  Which level of granularity does XtremIO deduplication run?

  A. Variable 8 kB

  B. Variable 32 kB

  C. Fixed 8 kB

  D. Fixed 32 kB

  Correct Answer: C

  EMC XtremIO(All-Flash) : SAN, inline deduplication, 8K fixed chunk size;

  References: https://www.linkedin.com/pulse/deduplication-fake-reality-mike-uzan

• Question 52:

  Based on XtremIO Data Protection, how many dedicated hot spare disks per X-Brick are required?

  A. 0

  B. 1

  C. 2

  D. 3

  Correct Answer: A

  XtremIO Data Protection (XDP) doesn't require any configuration, nor does it need hot spare drives. Insteadit uses "hot spaces" ?free space in the array.

  References: https://www.emc.com/collateral/white-paper/h13036-wp-xtremio-data-protection.pdf , page 23

• Question 53:

  A storage administrator is configuring SAN switches and zoning to connect an eight X-Brick XtremIO array. A VMware ESXi server is hosted on a blade chassis with 16 HBA ports. In addition, the SAN is composed of two separate SAN switches.

  What is the recommended XtremIO best practice for zoning?

  A. Two HBA connections per host connected to a single switch Multiple initiators/multiple targets per zone Maximum of 4 paths for each LUN per zone

  B. Connect a single storage controller to the first switch Connect a second storage controller to the second switch Single initiator/multiple targets per zone Maximum of 6 paths for each LUN per zone

  C. Connect all N1 storage controllers to the first switch Connect N2 storage controllers to the second switch Multipath all host ports to single LUNs per zone Maximum of 4 paths for each LUN per zone

  D. Multiple HBA connections per host Single initiator/single target per zone Maximum of 2 paths to each X-Brick for each initiator Each host connected to each SAN switch

  Correct Answer: B

  In an environment where a host with two HBAs (VMware Best Practice) is connected to two fabrics and storage array with two Storage Controllers (EMC VNX, for example) the host will have four paths to a LUN: 2 Controllers x 2 HBAs = 4 paths

  If you go to the extreme and configure your XtremIO with eight X-Brick, you have 16 controllers. Again, two HBAs per host and the max number of LUNs you can attach to an ESXi host will be 32... I understand, different OS'es may have different limits than VMware and this logic will not be applicable.

  If you have hit the limit of 1024 paths per host (1024 / 4 controllers / 2 HBAs = 128 LUNs) and need to provision more LUNs, the best way will be to re-zone the host to limit the number of X-Bricks / Controllers the host HBA can connect to.

  The following diagram displays the logical connection topology for 4 paths.

  

  Incorrect Answers:

  D: Eliminate single-initiator to single-target zones.

  References: http://vstrong.info/2015/11/18/vmware-host-zoning-for-multi-x-brick-emc-xtremio-storagearray/

• Question 54:

  A customer has purchased a two X-Brick XtremIO array with a physical XtremIO Management Server (XMS). The customer plans to use all Fibre Channel connectivity in the environment.

  What are the physical connectivity requirements for the cluster?

  A. 1 Copper Ethernet connection, 4 Fibre Channel Optical connections

  B. 3 Copper Ethernet connections, 8 Fibre Channel Optical connections

  C. 4 Copper Ethernet connections, 16 Fibre Channel Optical connections

  D. 5 Copper Ethernet connections, 8 Fibre Channel Optical connections

  Correct Answer: B

  EMC XTREMIO 4.0 SYSTEM SPECIFICATIONS

  

  References: http://www.aecl.com/AECWeb/media/Assets/PDF/h12451-xtremio-4-system-specificationsss.pdf

• Question 55:

  You are designing an XtremIO solution for a potential customer. If the server and storage information is available, which information should be documented regarding the customer's capacity expectations?

  A. Capacity requirements on a per data center basis Expandability/scalability Performance requirements determined on a server-to-server basis

  B. Capacity requirements on a per volume basis Expandability/scalability Performance requirements determined on a server-to-server basis

  C. Capacity requirements on a per volume basis Compression rates/scalability Performance requirements determined on a server-to-server basis

  D. Capacity requirements on a per data center basis Expandability/scalability Performance requirements determined holistically

  Correct Answer: B

• Question 56:

  An XtremIO administrator is having a problem with performance and is troubleshooting the issue. What is an accurate statement about I/O transfers?

  A. As I/O size increases, IOPs increase, and latency increases

  B. As I/O size increases, IOPs decrease, and bandwidth increases

  C. As I/O size decreases, IOPs increase, and bandwidth increases

  D. As I/O size decreases, IOPs decrease, and latency increases

  Correct Answer: A

  Large block I/O by nature incurs higher latency.

  References: Introduction to the EMC XtremIO STORAGE ARRAY (April 2015), page 6

• Question 57:

  A customer wants to purchase an XtremIO array. After the array is installed, the customer wants to initially disable encryption. What is the result of enabling encryption on an array that is already being used?

  A. Data will remain in place but the XtremIO cluster services will need to be temporarily shutdown.

  B. Data will remain in place and there will be no interruption to the XtremIO cluster services.

  C. Data will be erased but there will be no interruption to the XtremIO cluster services.

  D. Data will be erased and the XtremIO cluster services will be temporarily shutdown.

  Correct Answer: A

  Disable Encryption and Non-Encrypted Models This version [Ver. 4.0.2-65] allows disabling the Data at Rest Encryption (DARE), if desired. Disabling and Enabling is done when the cluster is stopped.

  References: https://samshouseblog.com/2015/12/29/new-features-and-changes-in-xtremio-ver-4-0-2-65/

• Question 58:

  A new 500 GB VM disk is created on a database that resides on an XtremIO LUN. The VMware administrator plans to provision the disk using the thick provisioned eager zeroed format.

  How much physical XtremIO capacity will be allocated during this process?

  A. 5 GB

  B. 10 GB

  C. 50 GB

  D. None

  Correct Answer: D

  XtremIO storage is natively thin provisioned, using a small internal block size. This provides fine-grained resolution for the thin provisioned space. All volumes in the system are thin provisioned, meaning that the system consumes capacity only when it is actually needed. XtremIO determines where to place the unique data blocks physically inside the cluster after it calculates their fingerprint IDs. Therefore, it never preallocates or thick-provisions storage space before writing.

  References: Introduction to the EMC XtremIO STORAGE ARRAY (April 2015), page 22

• Question 59:

  Based on best practice, what is the maximum number of paths a host should have to an XtremIO volume?

  A. 4

  B. 8

  C. 16

  D. 32

  Correct Answer: C

  The recommended maximum number of paths to storage ports per host is 16 as per the table below.

  

  References: https://www.emc.com/collateral/white-papers/h14475-wp-xtremio-brocade-best-practices.pdf? isPublic=false , page 12

• Question 60:

  Which multipathing software is supported by XtremIO?

  A. PowerPath/VE and NMP on ESXi hosts

  B. MPIO on non-clustered Microsoft Windows hosts only

  C. PowerPath/VE on Microsoft Windows VMs hosted by ESXi

  D. Native MPIO on IBM AIX clusters

  Correct Answer: A

  Noting the inefficiencies in VMware's NMP driver, EMC developed a set of drivers specifically designed to overcome these limitations and improve the performance and reliability of the data passing between an array and a server. EMC developed the PowerPath family of products optimized specifically for Linux, Microsoft Windows, and UNIX Operating Systems as well as PowerPath/VE for VMware vSphere and Microsoft Hyper-V hypervisors.

  PowerPath is installed on hosts to provide path failover, load balancing and performance optimization VPLEX engines (or directly to the XtremIO array if VPLEX is not used).

  Note: VMware, with the cooperation of its storage partners, developed a Native Multipathing Plug-in (NMP). VMware NMP was designed to distribute the load over all the available paths and provide failover protection in the case of path, port or HBA failure, but it has not been fully optimized to work with the controllers in a storage systems. VMware's NMP Round Robin policy does not have the intelligence that PowerPath has as PowerPath uses testing and diagnostics to continually monitor an environment to determine the optimal path for queuing requests and will adapt to current conditions.

  References: https://www.emc.com/collateral/analyst-reports/emc-taneja-group-powerpath-tb.pdf