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.

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’s also useful to be able to profile the I/O workload of applications already on a virtual platform.

So, what do we need to know? Well although I have a fairly well-rounded set of skills, I am more of a Microsoft guy than a Unix guy. As such I’m better at looking at I/O on Windows systems than anything else. Obviously this is something that I need to address a bit but it’s not exactly in the scope of this post.

Kevin Kline, a SQL MVP, has a short video hosted here that is targeted at physical SQL servers – the kind of load you’re likely to want to do this with.

There’s also a good MS Technet article about determining the I/O requirements for Exchange 2003 that’s a useful read.

Next up, I’d suggest having a look at SWAT. It’s Sun’s java based I/O monitoring tool.

Also, get to know vscsistats. Scott Drummonds (a guru in this area) has a VMware communities page that is a must read. Next, read the useful posts by Duncan Epping (YellowBricks), Gabrie van Zanten (Gabe’s Virtual World) and Gabe’s other post on making the output data Excel friendly.

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.

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

  1. In the vSphere Client, select Administration > vCenter Server Settings.
  2. In the settings list, select Advanced Settings.
  3. In the Key text box, type a key.
              1. Key                                                                     Filter Name
                config.vpxd.filter.vmfsFilter                                    VMFS Filter
                config.vpxd.filter.rdmFilter                                     RDM Filter
                config.vpxd.filter.SameHostAndTransportsFilter       Same Host and Transports Filter
                config.vpxd.filter.hostRescanFilter                           Host Rescan Filter
  4. NOTE If you turn off the Host Rescan Filter, your hosts continue to perform
    a rescan each time you present a new LUN to a host or a cluster.

  5. In the Value text box, type False for the specified key.
  6. Click Add.
  7. Click OK.

You are not required to restart the vCenter Server system.