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A database administrator has requested a disk for a virtual machine that will run an I/O intensive database application on an ESXi 5.x host. Which two disk types will best fit the needs of the application? (Choose two.)
A. Raw Device Mapped Disk
B. Thin Provisioned Disk
C. Thick Provision Lazy Zeroed Disk
D. Thick Provision Eager Zeroed Disk
Correct Answer: AD
Explanation/Reference:
I’m not sure about the RDM part of this but I’ll leave the answer as is.
"Virtualization of I/O intensive applications is nothing new. Traditionally the virtualization of these applications involved provisioning raw-device mappings over virtual disk files, whether warranted or not. VMware has proven the performance of VMFS to be on par with that of raw-device mappings as far back as ESX 3.0.1 "
The three types of disk provisioning are described below:
Thick provisioned lazy zeroed – The virtual disk is allocated all of its provisioned space and immediately made accessible to the virtual machine. A lazy zeroed disk is not zeroed up front which makes the provisioning very fast. However, because each block is zeroed out before it is written to for the first time there is added latency on first write.
Thick provisioned eager zeroed (Recommended for I/O intensive workloads) – The virtual disk is allocated all of its provisioned space and the entire VMDK file is zeroed out before allowing the virtual machine access. This means that the VMDK file will take longer to become accessible to the virtual machine, but will not incur the additional latency of zeroing on first write. For this reason the recommendation when deploying an I/O intensive application on VMFS is to use this provisioning method.
Thin provision – This method provides quick access to the virtual disk and increases storage utilization by allocating disk space on demand.
http://blogs.vmware.com/apps/2011/11/using-virtual-disks-for-business-critical-apps-storage.html
Exam F