EMC EMC Certifications E20-526 Questions & Answers

• Question 11:

  You need to design an Oracle solution for a customer. Which XtremIO best practices should be used in Oracle environments?

  A. Use a 512 byte LUN sector size for databases. Use Eager Zeroed Thick formatting for ESXi

  B. Use a 4 kB LUN sector size for databases. Use Lazy Zeroed Thick formatting for ESXi

  C. Align data on 4 kB boundaries. Use Thin formatting on ESXi

  D. Align data on 4 kB boundaries. Use Lazy Zeroed Thick formatting on ESXi

  Correct Answer: A

  The default setting for XtremIO volumes is 512e. It is recommended not to alter this in order to use 4K Advanced Format for Oracle Database deployments. There are no performance ramifications when using 512e volumes in conjunction with an Oracle database. On the contrary, 4K Advanced Format is rejected by many elements of the Oracle and Linux operating system stack.

  References: https://www.emc.com/collateral/white-papers/h13497-oracle-best-practices-xtremio-wp.pdf, page 20

• Question 12:

  A physical XtremIO Management Server (XMS) has failed and requires replacement. Which two software packages are required for recovery?

  A. XMS image and OVA image

  B. Xtremapp and OVA image

  C. XMS image and Xtremapp

  D. Xtremapp and MPIO

  Correct Answer: C

  The first step is to re-install the XMS image, in the event it is a physical XMS then you may install an image

  via a USB flash drive or for a virtual XMS simply deploy the provided VMware OVA image.

  The following step is to upload the XMS software to the images directory of the XMS and login with install

  mode ........

  Once logged into the XMS console with xinstall then perform the following sequence of steps:

  1. Configuration

  5. Perform XMS installation only

  11. Run XMS Recovery

  

  Options to choose when running the "XMS Recovery":

  

  References: https://davidring.ie/2015/02/20/emc-xtremio-redeploying-xms-xtremio-management-server/

• Question 13:

  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

  Correct Answer: A

  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 14:

  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

  Correct Answer: A

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

  Response time T(r) is calculated as: T(s) / (1 – Utilization), which here calculates to 32 ms/ (1-0.75) = 128

  ms.

  References: https://community.emc.com/thread/145100?tstart=0

• Question 15:

  

  As shown in the exhibit, a customer's environment is configured as follows: Dual X-Brick cluster 8 ESXi hosts with 2 HBAs Each ESXi hosts has 8 LUNs Each LUN is visible through 4 paths

  What should be the host queue depth setting per path?

  A. 64

  B. 128

  C. 256

  D. 1024

  Correct Answer: C

  The queue depth is per LUN, and not per initiator. Here there are 64 LUNs, each visible through 4 paths, which would indicate that 256 is a good choice for the queue depth setting.

  Note: As a general advice, for optimal operation with XtremIO storage, consider the following: Set the queue depth to 256.

  References: https://www.emc.com/collateral/white-paper/h14583-wp-best-practice-sql-server-xtremio.pdf

• Question 16:

  What is the maximum speed of the Fibre Channel ports on an XtremIO storage controller?

  A. 2 Gb/s

  B. 4 Gb/s

  C. 8 Gb/s

  D. 16 Gb/s

  Correct Answer: C

  Each Storage Controller includes two 8Gb/s Fibre Channel (FC) ports.

  References: Introduction to the EMC XtremIO STORAGE ARRAY (April 2015), page 8

• Question 17:

  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

  Correct Answer: C

  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 18:

  A customer is interested in purchasing XtremIO for their mission critical database applications that require the lowest possible response times. They have two data centers in which they want to introduce All-Flash arrays. However, they need a way to maintain true active/active access to all databases and application LUNs across both sites.

  What is the recommended solution to address the requirements?

  A. ViPR Controller with XtremIO

  B. RecoverPoint with XtremIO

  C. VPLEX Metro with XtremIO

  D. ViPR SRM with XtremIO

  Correct Answer: C

  The EMC VPLEX family is the next-generation solution for data mobility and access within, across and between data centers. VPLEX supports two configurations, local and metro. In the case of VPLEX Metro with the optional VPLEX Witness and Cross-Connected configuration, applications continue to operate in the surviving site with no interruption or downtime. Storage resources virtualized by VPLEX cooperate through the stack, with the ability to dynamically move applications and data across geographies and service providers.

  Incorrect Answers:

  A: EMC ViPR Controller is a software-defined storage platform that abstracts, pools and automates a data center's underlying physical storage infrastructure. It provides data center administrators with a single control plane for heterogeneous storage systems.

  B: The EMC RecoverPoint family provides cost-effective, local continuous data protection (CDP), continuous remote replication (CRR), and continuous local and remote replication (CLR) that allows for any-point-in-time data recovery and a new "snap and replicate" mechanism for local and remote replication (XRP). This enables replication for high-performance, low-latency applications.

  D: EMC ViPR SRM provides comprehensive monitoring, reporting and analysis for heterogeneous block, file and virtualized storage environments. It enables the users to visualize applications to storage dependencies, monitor and analyze configurations and capacity growth, and optimize their environment to improve return on investment.

  References: Introduction to the EMC XtremIO STORAGE ARRAY (April 2015) , page 63

• Question 19:

  A customer has two XtremIO clusters running 3.x software release. The customer just purchased a new XtremIO array that will be installed with the latest 4.x software release.

  What is the minimum number of XtremIO Management Server(s) that will be required to manage all clusters?

  A. 1

  B. 2

  C. 3

  D. 4

  Correct Answer: C

  The system operation is controlled via a stand-alone dedicated Linux-based server, called the XtremIO Management Server (XMS). A single XMS can manage multiple clusters. Multiple cluster management is supported from version 4.0 and up. System version 4.0 supports up to eight clusters managed by an XMS in a given site.

  References: Introduction to the EMC XtremIO STORAGE ARRAY (April 2015), page 48

• Question 20:

  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

  Correct Answer: D

  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