Objective 1.1 – Tools and Summary

Well, that one objective dealt with. Just another 30 odd to go. Don’t forget that reading is not everything, you need to have done as much of this stuff as possible. There are links to VMware’s product documentation throughout, be sure to be familiar with it as the language and methods that they use there should be the same as you’ll find in the VCAP exam – I hope.…

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Objective 1.1 – Analyse I/O Workloads

To put an application into a virtual environment you must first understand its I/O requirements to make sure that it will perform adequately on the storage that you have configured. This is very much like the process of determining how much CPU and Memory resource an application will need – it’s a necessary step. Of course you can miss it out and in the majority of cases that won’t be an issue but to keep your finger on capacity management  and to avoid possible problems it is best to follow a defined a repeatable set of steps. It’…

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Objective 1.1 - LUN Masking and PSA-related Commands

What is LUN masking? explains what LUN masking is in layman’s terms (in case you have a NAS only background). See Storage Masking? for the Yellow Bricks advice on LUN masking. For an overview of PSA and commands, see VMware vSphere 4.1 PSA. Also see the vSphere CLI guide, vSphere Command-Line Interface Installation and Reference Guide.…

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Objective 1.1 - vCenter Storage Filters

From the ESX Configuration Guide. When you perform VMFS datastore management operations, vCenter Server uses default storage filters. The filters help you to avoid storage corruption by retrieving only the storage devices, or LUNs, that can be used for a particular operation. Unsuitable LUNs are not displayed for selection. You can turn off the filters to view all LUNs. Before making any changes to the LUN filters, consult with the VMware support team. You can turn off the filters only if you have other methods to prevent LUN corruption. Procedure In the vSphere Client, select Administration > vCenter Server Settings.…

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Objective 1.1 - Raw Device Mapping (RDM)

Read Performance Characterization of VMFS and RDM Using a SAN. It may be for ESX 3.5 but still holds true. The conclusion from the document is: VMware ESX Server offers two options for disk access management—VMFS and RDM. Both options provide clustered file system features such as user‐friendly persistent names, distributed file locking, and file permissions. Both VMFS and RDM allow you to migrate a virtual machine using VMotion. This study compares the performance characteristics of both options and finds only minor differences in performance. For random workloads, VMFS and RDM produce similar I/O throughput. For…

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Objective 1.1 - VMware Storage Best Practices

Obviously the choice of storage vendor and the underlying technologies play a part here but there are some general guidelines that apply regardless. VMware themselves have a short page on this which I have copied below: Many of the best practices for physical storage environments also apply to virtual storage environments. It is best to keep in mind the following rules of thumb when configuring your virtual storage infrastructure: Configure and size storage resources for optimal I/O performance first, then for storage capacity. This means that you should consider throughput capability and not just capacity. Imagine a very large…

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Objective 1.1 - RAID levels for VM workloads

There isn’t a single rule for this – there are more like thousands of rules! Basically have an idea of what workloads VMs are generating in terms of IO and try to balance them out but also bear in mind that write intensive loads will perform better on RAID 10 than on RAID 5 but RAID 10 uses more disks than RAID 5 does. Whilst not specifically related to RAID and it talks about EMC storage, Optimal VM Placement offers some interesting thoughts and mentions the alarms that can be set in vCenter that are usueful to monitor problems: VM…

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