EMC EMC Certifications E20-526 Questions & Answers

• Question 61:

  A customer has recently purchased an XtremIO 10 TB single X-Brick cluster for an implementation of Oracle RAC. The customer wants your help with integrating Oracle with their new XtremIO cluster. The customer has three DATA disk groups, two REDO disk groups, and four FRA disk groups.

  How many XtremIO LUNs should be assigned to the FRA disk groups?

  A. 2

  B. 4

  C. 6

  D. 8

  Correct Answer: D

  Best practice is to use four LUNs for the DATA disk group to allow the host to use simultaneous threads. The REDO and FRA disk groups should use two LUNs each.

  References: https://community.emc.com/community/connect/everything_oracle/blog/2016/03/31/bestpractises-of-vblock-on-xtremio-with-oracle-databases-part-i

• Question 62:

  A customer has a large ESX server environment they are considering deploying to XtremIO for a VDI implementation. To determine a baseline of the environment, you are proceeding with documenting each server's CPU, NIC, and disk utilization statistics. The customer has provided you with direct CLI access to the servers to conduct this assessment.

  Which utility should be used to monitor these performance parameters?

  A. esxtop

  B. resxtop

  C. top

  D. iostat

  Correct Answer: B

  resxtop is a command to retrieve performance statistics. This command is included in vSphere command line interface (CLI) and is part of the vSphere Management Assistant (vMA), which is an equivalent to esxtop that runs only inside an ESX service console.

  Incorrect Answers:

  A: esxtop runs only inside an ESX service console.

  D: Use the iostat command to report statistics about disk input and output, and to produce measures of throughput, utilization, queue lengths, transaction rates, and service time.

  References: www.emc.com/collateral/TechnicalDocument/docu5265.pdf, page 22

• Question 63:

  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

  Correct Answer: B

  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-arraymanagement

• Question 64:

  How can REST API commands be run to manage and monitor an XtremIO cluster?

  A. From the REST API CLI built into each X-Brick

  B. From the REST API GUI built into each X-Brick

  C. From a third-party GUI

  D. From the REST API tab in the XMS GUI

  Correct Answer: C

  The XtremIO's RESTful API allows HTTPS-based interface for automation, orchestration, query and provisioning of the system. With the API, third party applications can be used to control and fully administer the array.

  Normally you would access the API using some form of programming/scripting language, such as Python or Perl. However for the purposes of learning or testing concepts there are a number of tools that work better, such as HTTPRrequester and curl.

  *

  Curl is a command-line tool that exists in all Linux distributions, and is available for most other Unix OSes as well as Windows. To use curl to access XtremIO you'll need to pass it a few options, such as the username/password to access the array (any valid account on the XtremIO XMS will work), the URL of the API, and potentially a few options such as -k to tell curl not to validate the SSL certificate (presuming you don't have a valid certificate installed), and -s (silent) to stop curl displaying it's progress as it downloads the response.

  *

  HTTPRequester is a browser extension that is available for both Chrome and Firefox. As with for curl, you'll need to provide a username/password, which is done by clicking on the

  "Authentication..." box, which adds two boxes below the URL for the username and the password.

  

  References: https://blog.docbert.org/using-the-xtremio-rest-api-part-1/

• Question 65:

  You have been asked to design an XtremIO storage array solution that will be used for two large applications workloads. One overload will generate approximately 150,000 write IOPs with an average 4 kB I/O size. The second write workload will have an average I/O size of 128 kB and will generate approximately 2 GB/s of throughput.

  At a minimum, how many X-Bricks are needed in a single cluster to meet this requirement?

  A. 2

  B. 4

  C. 6

  D. 8

  Correct Answer: A

  Second write workload IOPS = 2 GB/s divided by 128 kB = 2 x 1,073,741,824 / (128 x 1,024) = 16384

  IOPs.

  Total IOPS required would be 150,000, from the first workload, plus 16384, totaling 166384.

  A 2 X-Brick cluster provides 300K Read/write IOPS so it would be adequate.

  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.

  Note: Choose an EMC XtremIO system and scale out linearly by adding more XtremIO X-Bricks.

  

  References: https://store.emc.com/en-us/Product-Family/EMC-XtremIO-Products/EMC-XtremIO-All-FlashScale-Out-Array/p/EMC-XtremIO-Flash-Scale-Out

• Question 66:

  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

  Correct Answer: B

  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 67:

  When using the XtremIO PoC Toolkit, what is the purpose of the Age phase?

  A. Continuously write to a specific range of logical block addresses to test Flash durability

  B. Overwrite each LUN multiple times to ensure they contain all unique data

  C. Test the performance of the All-Flash array with non-production static data

  D. Scatter writes across the entire array to simulate ordinary use of the system

  Correct Answer: D

  Proceed with filesystem aging by doing random overwrite cycles.