EMC E20-526 Online Practice Questions and Exam Preparation

EMC E20-526 Online Questions & Answers

• Question 1:

  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
  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

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  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-storage-array/

• Question 2:

  A user attempts to create a quorum disk for a host cluster. Volume parameters are: Size = 1000 kB Name 1MB_Vol

  However, the volume creation fails. What caused the process to fail?

  A. Quorum disks cannot have an 8kB block size
  B. Volume size is too small
  C. Volume name is invalid
  D. XtremIO volumes cannot be quorum disks
  B. Volume size is too small

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  The volume size must be specified in MB, GB, TB, and not in KB. Incorrect Answers:

  D: Quorum disks on XtremIO

  The SAN Volume Controller cluster will select disks that are presented by the XtremIO storage system as quorum disks. To maintain availability for the cluster, ideally each quorum disk should reside on a separate disk subsystem.

  The quorum device can be any disk device that is shared between two or more nodes. EMC Symmetrix, VNX series, or XtremIO devices are commonly used for this purpose. References: https://vcdx133.com/2014/09/14/emc-xtremio-provisioning-a-lun/

• Question 3:

  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
  B. Application response time and rapid boot times
  C. Sufficient capacity and performance

• Question 4:

  How many management IP addresses are required on a single XtremIO storage controller?

  A. 1
  B. 2
  C. 3
  D. 4
  A. 1

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  References: https://docs.openstack.org/juno/config-reference/content/XtremIO-cinder-driver.html#xtremio-management-ip

• Question 5:

  A storage administrator is adding both an XtremIO and third-party storage arrays to their existing infrastructure. The administrator is using ViPR SRM to monitor the environment. Which requirement is needed to implement this solution?

  A. A single third-party Solution Pack is required to manage both storage arrays
  B. Each storage needs its own Solution Pack
  C. Each storage array requires two Solution Packs; one for monitoring and one for performance
  D. A single XtremIO Solution Pack is required to manage both storage arrays
  B. Each storage needs its own Solution Pack

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  References: https://www.emc.com/techpubs/vipr/understanding_solutionpacks-3.htm

• Question 6:

  A customer has recently deployed an XtremIO 20 TB two X-Brick cluster to run an existing instance of Oracle RAC previously leveraging VNX for back-end storage. The application environment uses a block size of 1 MB. Multiple tables are in use with the PARALLEL_DEGREE_POLICY variable set to AUTO.

  The customer wants your help with tuning the DB_FILE_MULTIBLOCK_READ_COUNT parameter for best performance with XtremIO. Which values should be recommended for tuning the DB_FILE_MULTIBLOCK_READ_COUNT parameter in the Oracle RAC environment?

  A. 8 or 16
  B. 24 or 32
  C. 64 or 128
  D. 256 or 512
  C. 64 or 128

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  Oracle Database performs I/O on data files in multiples of the database block size (db_block_size), which is 8KB by default. The default Oracle Database block size is optimal on XtremIO. XtremIO supports larger block sizes as well. In the

  case of multiblock I/O (e.g., table/index scans with access method full), one should tune the Oracle Database initialization parameter db_file_multiblock_read_count to limit the requests to 128KB.

  Therefore, the formula for db_file_multiblock_read_count is:

  db_file_multiblock_read_count = 128KB / db_block_size

  In our case the block size is 1 MB, so the formula db_file_multiblock_read_count is 1 MB/ 8KB = 1024/8 = 128

  References: https://www.emc.com/collateral/white-papers/h13497-oracle-best-practices-xtremio-wp.pdf, page 21

• Question 7:

  A customer is considering migrating their existing non-EMC storage arrays to an XtremIO array. The current environment consists of 350 servers running VMware ESXi 5.5 with 5000 virtual machines. The customer has various tools in place to monitor performance and collect statistics. On average, their service time is 32 ms and utilization is at 75%. In the past, the customer has had performance issues.

  Based on Little's Law, what is the calculated response time on the existing environment?

  A. 128 ms
  B. 192 ms
  C. 256 ms
  D. 332 ms
  A. 128 ms

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  Disk service time T(s) = 32 ms (service time for one I/O).

  Response time T(r) is calculated as: T(s) / (1

• Question 8:

  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
  A. 1 cluster with 2 X-Bricks

• Question 9:

  Which operation is performed when an XtremIO Snapshot is created?

  A. Pointers to the ancestor metadata are created for the snapshot
  B. Space equal to the size of the ancestor is allocated to the snapshot
  C. A reserved space is created for new snapshot data
  D. A deduplication pass is immediately run against the snapshot
  A. Pointers to the ancestor metadata are created for the snapshot

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  When a snap is created, the following steps occur: 1) Two empty containers are created in-memory 2) Snapshot SCSI personality is pointing to the new snapshot sub-node 3) The SCSI personality which the host is using, is linked to the second node in the internal data tree

  References: EMC RECOVERPOINT REPLICATION OF XTREMIO, Understanding the essentials of RecoverPoint Snap-based replication for XtremIO, page 8 https://www.emc.com/collateral/white-papers/h14296-wp-recoverpoint-replicationof-xtremio.pdf

• Question 10:

  A customer currently uses XtremIO native remote replication with four RPAs and a 1 GB WAN link to asynchronously protect all production data. Management has decided that all data stored on the XtremIO must now be protected at the disaster recovery site by synchronous replication.

  How can this be achieved?

  A. Set the Link Policy to Synchronous, Dynamic by throughput
  B. Purchase four additional RPAs.
  C. Set the Link Policy to Synchronous, Dynamic by latency
  D. Use a VPLEX splitter
  D. Use a VPLEX splitter

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  XtremIO with VPLEX provides for both synchronous and asynchronous replication.

  Note: The engine of RecoverPoint is the RecoverPoint Appliance (RPA).

  Incorrect Answers:

  A, B, C: XtremIO with Physical RPA - No Synchronous option available, only asynchronous replication as this uses snapshot shipping.

  References: Introduction to the EMC XtremIO STORAGE ARRAY (April 2015), page 55