A quick post that is triggered by a tweet from @GernotNusshall I saw passing today. He wanted to know how to find the maximum IOPS values over the last 5 minutes for a number of VMs. The IOPS values are readily available from the vSphere statistics but the problem is that the values are returned as summation values over the measuring interval and that you have a read and a write value.
An ideal job for PowerShell to get the values Gernot was after.
In an earlier post, see Hitchhiker’s Guide to Get-EsxTop – Part 1, I described my first experiences with the new Get-EsxTop cmdlet. While the use of the cmdlet is rather straightforward, the data it returns is not so easy to interprete. Luckily Carter intercepted a secret cable that allows us to actually use the data returned by the cmdlet.
The following is my first attempt to write a wrapper around the Get-EsxTop cmdlet. The idea is to have a script that produces statistical data similar to what resxtop produces.
Continue reading Hitchhiker’s Guide to Get-EsxTop – Part 2 – The wrapper
SIOC (Storage IO Control) is apparently a hot topic. There have been an important number of posts since it was made available with vSphere 4.1. On this blog, in my Automate SIOC post, you can find functions to verify and activate/deactivate SIOC from your PowerShell script.
A recent post on Yellow-Bricks, called Enable Storage IO Control on all Datastores! got quite a few comments and Tweets.
I was intrigued by one of the comments on Twitter that stated that the users didn’t understand what SIOC was all about. From several posts on SIOC I came to understand that the non-VI workload event would be fired when SIOC doesn’t see any latency improvements when it throttles the storage queue. Simple enough, but is there any data available that can make this visible ?
In a previous post in this series (see PowerCLI & vSphere statistics – Part 2 – Come together), I showed the usefulness of the Group-Object cmdlet when working with statistical data. The script in that post grouped data samples for each hour together, which made it much easier to calculate the hourly average. With the Group-Object cmdlet you avoid numerous nested if- or switch-statements.
And best of all, you don’t have to code the grouping yourself, it was all done for you by the PowerShell Team.
So make sure this cmdlet belongs to your basic PowerShell repertoire. It will prove invaluable when processing statistical data.
This post will show you several of the different options you have to group statistical data together. And I will illustrate each of these with a sample script.
Continue reading PowerCLI & vSphere statistics – Part 4 – Grouping
In PowerCLI & vSphere statistics – Part 1 – The basics I briefly mentioned instances. In this post I’ll go a bit deeper into that subject.
And to demonstrate it all I will use part of the esxtop post on Yellow Bricks. In that post Duncan compiled, from various sources, a number of “common sense” thresholds that you can use in esxtop to show you possible problems with your hosts and/or guests.
Since I’m not sitting 24/7 behind an ESX/ESXi console, I looked for a way to let PowerCLI/PowerShell do that for me 😉
Continue reading PowerCLI & vSphere statistics – Part 3 – Instances
The end of my previous post in this series, see PowerCLI & vSphere statistics – Part 1 – The basics, showed how you could get the statistical values for a specific day.
Depending on the point in time for which you request the values, the sampling interval will be different. For example Historical Interval 2 will return values measured over 30 minute intervals. See also the schematic I included in the previous post.
This sample interval is not always what you want for your reports. Suppose you want to always report hourly values and only for working hours during business days. This post will show you how to accomplish that.
Continue reading PowerCLI & vSphere statistics – Part 2 – Come together
Another popular subject in the VMTN PowerCLI community are statistics. Quite often it’s not entirely clear to the user what is available, how the data can be extracted and how PowerShell/PowerCLI can be used to convert the raw metrics into usable reports.
Before you can fully use all that is available, there are a few key concepts that you should understand.
In this series I will try to explain some common questions.
