Dell EMC e20-526 practice test
Technology Architect, XtremIO Solutions Specialist Exam
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
Answer:
C
Explanation:
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 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
Answer:
C
Explanation:
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
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
Answer:
B
Explanation:
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 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
Answer:
D
Question 6
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
Answer:
B
Explanation:
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 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
Answer:
B
Explanation:
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
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
Answer:
B
Explanation:
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
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
Answer:
D
Explanation:
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
You have conducted a meeting with a companys 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
Answer:
B,C
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
Answer:
A
Explanation:
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
Answer:
C
Explanation:
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
Answer:
A
Explanation:
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 Littles Law, what is the calculated response time on the existing environment?
- A. 128 ms
- B. 192 ms
- C. 256 ms
- D. 332 ms
Answer:
A
Explanation:
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
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
Answer:
C
Explanation:
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