EMC EMC Certifications E20-526 Questions & Answers

• Question 1:

  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

  Correct Answer: C

  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-designconsiderations.pdf, page 57

• Question 2:

  When installing a physical XtremIO Management Server (XMS) station, which requirement must be met?

  A. XMS must be able to access one of the management ports on one X-Brick storage controller in the cluster

  B. XMS must be able to access only the management ports on the first X-Brick's storage controllers

  C. XMS must be able to access all management ports on the X-Brick storage controllers

  D. XMS must be able to access all management ports on at least two X-Brick storage controllers in the cluster

  Correct Answer: C

  The XMS must access all management ports on the X-Brick Storage Controllers, and must be accessible by any GUI/CLI client host machine. References: Introduction to the EMC XtremIO STORAGE ARRAY (April 2015), page 48

• Question 3:

  A customer has a group of applications that need storage which can provide low response times. The total I/O requirements are 75,000 IOPs with a 4 kB block size. They will have 500 LUNs and need to keep 30 daily snapshots of each LUN.

  What is the smallest XtremIO configuration that will meet their needs?

  A. 1 cluster with 2 X-Bricks

  B. 1 cluster with 4 X-Bricks

  C. 2 clusters with 1 X-Brick each

  D. 2 clusters with 2 X-Bricks each

  Correct Answer: A

• Question 4:

  When creating XtremIO volumes for a host, which operating systems will benefit by changing the default logical block size for applications consisting of 4 KB I/Os?

  A. Microsoft Windows and RHEL

  B. VMware ESX and Microsoft Windows

  C. RHEL and IBM AIX

  D. Sun Solaris and HP-UX

  Correct Answer: B

  With VMware ESX 5.5, the VMware hypervisor cannot work with LUNs that use a logical block size of 4K. When using VMware, be sure to specify Normal (512 LBs) from your XtremIO array.

  References: https://gruffdba.wordpress.com/2015/08/02/4k-logical-block-size-size-fails-on-vmware/

• Question 5:

  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

  Correct Answer: B

  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-athin-provisioned-san-vol-take

• Question 6:

  A customer wants to use the Cinder driver to manage XtremIO storage in an OpenStack environment. What is a potential concern?

  A. Compression is not supported

  B. Deduplication is not supported

  C. Snapshots of snapshots are not supported

  D. Volume expansion cannot be reversed

  Correct Answer: D

  Incorrect Answers:

  B: OpenStack Cinder features include:

  Clone a volume: With inline deduplication, compression and thin provisioning.

  C, D: EMC XtremIO OpenStack Block Storage driver, supported operations: Create, delete, clone, attach, and detach volumes Create and delete volume snapshots Create a volume from a snapshot Copy an image to a volume Copy a volume to an image Extend a volume

  References: https://docs.openstack.org/juno/config-reference/content/XtremIO-cinder-driver.html https://www.emc.com/collateral/data-sheet/h13287-ds-xtremio-openstack.pdf

• Question 7:

  What are common storage array mechanisms?

  A. Log structuring and RAID

  B. Post-processing and metadata logging

  C. RAID and metadata log structuring

  D. Metadata logging and RAID

  Correct Answer: B

  XtremIO's snapshot technology is implemented by leveraging the content-aware capabilities of the system (Inline Data Reduction), optimized for SSD media, with a unique metadata tree structure.

  XtremIO leverages a proprietary flash-optimized data protection algorithm (XtremIO Data Protection or XDP), which provides performance that is superior to any existing RAID algorithm.

  References: Introduction to the EMC XtremIO STORAGE ARRAY (April 2015), page 33

• Question 8:

  You have conducted a meeting with a company's Chief Technology Officer (CTO). The CTO wants an XtremIO solution to meet their business needs. The CTO wants you to review the proposed solution with their desktop administrator to identify any additional requirements.

  What are two key considerations to discuss with the desktop administrator?

  A. Rapid desktop deployment and operational ease of use

  B. Application response time and rapid boot times

  C. Sufficient capacity and performance

  D. Ease of management and ability to customize end-user desktops

  Correct Answer: BC

• Question 9:

  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

  Correct Answer: D

  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/

• Question 10:

  A Linux administrator is attaching a new RHEL server to their XtremIO storage array. Which configuration setting should be changed?

  A. Enable Logical Volume Manager

  B. Modify the file system block size

  C. Disable HBA Queue Depth

  D. Disable I/O elevators

  Correct Answer: B

  The block size for both Oracle Cluster Registry (OCR) and Cluster Synchronization Services (CSS) voting files are 512 bytes. I/O operations to these file objects are therefore sized as a multiple of 512 bytes. This is of no consequence since the best practice with XtremIO is to create volumes with 512e formatting.

  References: https://www.emc.com/collateral/white-papers/h13497-oracle-best-practices-xtremio-wp.pdf , page 22