Creating and Configuring Storage Devices - Mastering VMware vSphere 5.5 - page 378

connectivity in place, coni gure LUNs and VMFS datastores and/or NFS exports/NFS datas-
tores using the predictive or adaptive model (or a hybrid model). Use Storage vMotion to
resolve hot spots and other non-optimal VM placement.
Master It What would best identify an oversubscribed VMFS datastore from a perfor-
mance standpoint? How would you identify the issue? What is it most likely to be? What
would be two possible corrective actions you could take?
Master It A VMFS volume is i lling up. What are three possible nondisruptive correc-
tive actions you could take?
Master It What would best identify an oversubscribed NFS volume from a performance
standpoint? How would you identify the issue? What is it most likely to be? What are two
possible corrective actions you could take?
Coni gure storage at the VM layer. With datastores in place, create VMs. During the cre-
ation of the VMs, place VMs in the appropriate datastores, and employ selective use of RDMs
but only where required. Leverage in-guest iSCSI where it makes sense, but understand the
impact to your vSphere environment.
Master It Without turning the machine off, convert the virtual disks on a VMFS volume
from thin to thick (eagerzeroedthick) and back to thin.
Master It Identify where you would use a physical compatibility mode RDM, and con-
i gure that use case.
Leverage best practices for SAN and NAS storage with vSphere. Read, follow, and lever-
age key VMware and storage vendors' best practices/solutions guide documentation. Don't
oversize up front, but instead learn to leverage VMware and storage array features to monitor
performance, queues, and backend load—and then nondisruptively adapt. Plan for perfor-
mance i rst and capacity second. (Usually capacity is a given for performance requirements
to be met.) Spend design time on availability design and on the large, heavy I/O VMs, and
use l exible pool design for the general-purpose VMFS and NFS datastores.
Master It Quickly estimate the minimum usable capacity needed for 200 VMs with
an average VM size of 40 GB. Make some assumptions about vSphere snapshots. What
would be the raw capacity needed in the array if you used RAID 10? RAID 5 (4+1)? RAID
6 (10+2)? What would you do to nondisruptively cope if you ran out of capacity?
Master It Using the coni gurations in the previous question, what would the minimum
amount of raw capacity need to be if the VMs are actually only 20 GB of data in each
VM, even though they are provisioning 40 GB and you used thick on an array that didn't
support thin provisioning? What if the array did support thin provisioning? What if you
used Storage vMotion to convert from thick to thin (both in the case where the array sup-
ports thin provisioning and in the case where it doesn't)?
Master It Estimate the number of spindles needed for 100 VMs that drive 200 IOPS each
and are 40 GB in size. Assume no RAID loss or cache gain. How many if you use 500 GB
SATA 7200 RPM? 300 GB 10K Fibre Channel/SAS? 300 GB 15K Fibre Channel/SAS?
160 GB consumer-grade SSD? 200 GB Enterprise Flash?