EMC E20-526 Online Practice Questions and Exam Preparation

EMC E20-526 Online Questions & Answers

• Question 11:

  A storage administrator wants to re-use some of their XtremIO thin provisioned disks attached to a Microsoft Windows 2012 host. However, the administrator notices that "Quick Format" of the drives is taking a long time to complete. This has an impact on the overall performance.

  What should be recommended to minimize the performance impact?

  A. Disable the I/O elevator feature on the Windows host while formatting
  B. Temporarily disable the UNMAP feature on the Windows host during formatting
  C. Adjust the execution throttle value on the Windows host
  D. Change the disk format to thick provisioned
  B. Temporarily disable the UNMAP feature on the Windows host during formatting

  ---

  It is related to TRIM/UNMAP, which is enabled per default in Server 2012(R2).

  References: https://serverfault.com/questions/679211/quick-format-of-lun-in-server-2012r2-hosted-on-a-thin-provisioned-san-vol-take

• Question 12:

  How should a storage administrator navigate to different XtremIO clusters from the XMS GUI if the administrator has more than one cluster managed by the same XMS?

  A. Click the Cluster Name on the Menu bar near the top of the screen
  B. Click the Inventory List button on the Menu bar
  C. Click the Administration tab and locate the Cluster Name
  D. Click the Cluster Name on the Status bar at the bottom of the screen
  B. Click the Inventory List button on the Menu bar

  ---

  From the menu bar, the Inventory icon is to be clicked to display the Inventory workspace. This workspace takes the place of the Hardware workspace in earlier versions of the XtremIO GUI. With the All Clusters tab selected, we can see a list of all the hardware elements in the managed clusters.

  

  Note: With time, additional clusters can be added to a deployed XMS. In addition, a cluster can be easily moved from one XMS to another. All management interfaces (GUI/CLI/REST) offer inherent multi-cluster management capabilities. Multiple cluster management is supported from version 4.0 and up.

  References: https://community.emc.com/community/connect/everything_oracle/blog/2015/08/27/xtremio-40-multi-array-management

• Question 13:

  At which point is data compressed when a host sends data to the XtremIO storage system?

  A. Inline before data is written to the SSD
  B. Once data is written to the storage controller
  C. After data is written to the SSDs
  D. After data is in SSD cache
  A. Inline before data is written to the SSD

  ---

  XtremIO inline data deduplication and inline data compression services are inline, all the time.

  References: https://www.emc.com/collateral/faq/faq-million-dollar-guarantee-rp-2016.pdf

• Question 14:

  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
  A. PowerPath/VE and NMP on ESXi hosts

  ---

  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

• Question 15:

  A customer has decided to use VMware Horizon View as their desktop virtualization technology. Their VDI environment will consist of XtremIO storage and ESXi hosts. They are looking for increased speed and low latencies while performing file copy operations.

  What should the setting for VAAI XCOPY I/O size be set to in order to achieve this requirement?

  A. 8 kB
  B. 63 kB
  C. 256 kB
  D. 4 MB
  C. 256 kB

  ---

  The VAAI XCOPY I/O size of 256 kB gives the best performance. 4 MB is the default value.

  References: https://www.emc.com/collateral/white-papers/h14279-wp-vmware-horizon-xtremio-design-considerations.pdf, page 57

• Question 16:

  A customer is considering XtremIO storage for their current Virtual Desktop Infrastructure (VDI) deployment. The customer wants information on the benefits of an XtremIO solution. What are the benefits of an XtremIO solution for this environment?

  A. Latency is less than 1 ms for all large I/O sizes, deduplication with compression, and scales linearly
  B. Latency is less than 1 ms for large I/O sizes, deduplication and compression, and no reduction in power and cooling costs
  C. Latency is less than 1 ms for small I/O sizes, scales linearly, and slightly higher cost/IOP/GB than hybrid arrays
  D. Latency is less than 1 ms for small I/O sizes, deduplication and compression, and scales linearly
  A. Latency is less than 1 ms for all large I/O sizes, deduplication with compression, and scales linearly

  ---

  Storage capacity and performance scale linearly, such that two X-Bricks supply twice the IOPS, four X-Bricks supply four times the IOPS, six X-Bricks supply six times the IOPS and eight X-Bricks supply eight times the IOPS of the single X-Brick configuration. However, the latency remains consistently low (less than 1ms) as the system scales out. The sub-millisecond latency is validated by actual test results, and is determined according to the worst-case scenario.

  References: Introduction to the EMC XtremIO STORAGE ARRAY (April 2015), page 37

• Question 17:

  An administrator receives an error on an XtremIO array while performing snapshot refreshes to a production volume. What is a potential cause for this issue?

  A. Refresh of the production volume is not supported
  B. Volume was not unmapped on the XtremIO cluster
  C. Only snapshot-to-snapshot refresh is supported
  D. Volume was not unmounted on the host
  D. Volume was not unmounted on the host

  ---

  The workflow for refreshing XtremIO Snapshots, containing Oracle Database files, consists of the following five simple steps:

  1.

  Shut down the database instances with files in the target Snapshot Set.

  2.

  Dismount the ASM disk group (or file systems) involved.

  3.

  Refresh the Snapshot via XtremIO GUI (or CLI or RESTful API).

  4.

  Mount the ASM disk groups (or file system) involved.

  5.

  Start the database instances.

  This entire workflow is measured in seconds (not minutes).

  Incorrect Answers:

  A: The refresh command is a powerful tool for test and development environments and for the offline processing use case. With a single command, a snapshot of the production volume or CG is taken and the SCSI face of the volume, which was mapped to the test and development application, is moved to it. This allows the test and development application to work on current data without the need to copy data or to rescan.

  References: https://www.emc.com/collateral/white-papers/h14485-xtremio-snapshot-refresh-oracle-databases.pdf, page 8

• Question 18:

  What is a method to establish an XMCLI session?

  A. Use the PuTTY SSH tool configured for the serial port and xmsupload credentials
  B. Use the Telnet SSH tool configured on Port 443 and root credentials
  C. Use the CLI terminal in the Administration tab and root credentials
  D. Use the PuTTY SSH tool configured for Port 22 and xmsadmin credentials
  D. Use the PuTTY SSH tool configured for Port 22 and xmsadmin credentials

  ---

  The system's Command Line Interface (CLI) allows administrators and other system users to perform supported management operations. It is preinstalled on the XMS and can be accessed using the standard SSH protocol.

  PuTTY is an SSH and telnet client.

  The standard TCP port 22 has been assigned for contacting SSH servers.

  You can login using the builtin xmsadmin account.

  References: Introduction to the EMC XtremIO STORAGE ARRAY (April 2015), page 50

• Question 19:

  A storage administrator wants to add a volume to their XtremIO storage array using the RESTful API. Which RESTful method should be used to complete this task?

  A. HTTP POST
  B. HTTP PATCH
  C. HTTP LINK
  D. HTTP PUT
  A. HTTP POST

  ---

  An example of a generic wrapper function that queries XtremIO REST API using HTTP/POST to create a new object with specified properties.

  

  References: https://www.emc.com/collateral/white-papers/h14980-wp-accelerate-sql-lifecycle-management.pdf

• Question 20:

  Where is the XtremIO VSS hardware provider package installed?

  A. On all X-Bricks in the cluster
  B. On the XMS
  C. Factory-installed on the array
  D. On the backup server
  D. On the backup server

  ---

  In order to use the XtremIO VSS provider it must be installed on the server where we want to do an application consistent snapshot. References: http://muegge.com/blog/tag/xtremio/