Poster of PowerCLI commands for VMware 4.0 +
Poster of PowerCLI commands for VMware 5.0
The new poster adds to the original vSphere PowerCLI core cmdlets and allow you to quickly reference cmdlets from the following :
Courtesy of labguides.com – Check it Out!
What is the AutoLab?
The AutoLab is a quick easy way to build a vSphere environment for testing and learning using a single desktop or laptop PC and VMware Workstation, Fusion or ESXi. The whole lab runs in VMs on that one PC, even ESXi runs in a VM and can then run it’s own VMs.
What’s in the AutoLab?
The Autolab download contains a set of shell VMs and a lot of automation. Once built the lab contains two ESXi servers, a Windows Domain controller, a Windows Virtual Centre, a FreeNAS storage appliance and a FreeSCO Router to link it to the outside world
What can I do with the AutoLab?
Hardware Requirements
Will my laptop/PC be able to run the AutoLab?
If your laptop has 8GB of RAM and a recent CPU you should be able to run the lab. Here is my three year old laptop that is upgraded to 8GB of RAM running the whole lab including VMs running on the ESXi servers inside the lab.
Where can I get the AutoLab?
vBrownBags are a series of online webinars held using GotoMeeting and covering various Virtualization & VMware Certification topics.
VMDK Files
These are the disk files that are created for each virtual hard drive in your VM. There are 3 different types of files that use the vmdk extension, they are:
Sometimes, it is worth doing a storage reclamation exercise through all your VMware Datastores in order to remove old folder, files and to check that nothing miscellaneous is going on.
What can you find?
In vCenter > Datastores > Performance Tab, you can find the graph showing all the files it can detect with the selection “Other VM Files” OR “Other” which is what we’re interested in.
When we checked this out on the Host back-end logged in via Putty, we can see the below. The ./ files are not usual to find on LUNs/Datstores and indicate that there are SAN snapshots existing on here
/vmfs/volumes/4e0da454-902c23bf-cb36-e61f13f7c69b # ls -l
SERVER01
SERVER02
SERVER03
/vmfs/volumes/4e0da454-902c23bf-cb36-e61f13f7c69b # find . -exec ls -lh {} \; | grep flat
SERVER01-flat.vmdk
SERVER01_1-flat.vmdk
SERVER01_2-flat.vmdk
SERVER01_3-flat.vmdk
./SERVER01/SERVER01_3-flat.vmdk
./SERVER01/SERVER01_2-flat.vmdk
./SERVER01/SERVER01_1-flat.vmdk
./SERVER01/SERVER01-flat.vmdk
Conclusion
You will need to ask your Storage Admin to check out your LUNs and make sure that any old snapshots are either required or can be deleted.
It is worth keeping an eye on all of this as we found we had nearly 2TB of LUN Snapshots lurking around taking up valuable and expensive storage space.
What is Storage I/ Control?
*VMware Enterprise Plus License Feature
Set an equal baseline and then define priority access to storage resources according to established business rules. Storage I/O Control enables a pre-programmed response to occur when access to a storage resource becomes contentious
With VMware Storage I/O Control, you can configure rules and policies to specify the business priority of each VM. When I/O congestion is detected, Storage I/O Control dynamically allocates the available I/O resources to VMs according to your rules, enabling you to:
How is it configured?
It’s quite straight forward to do. First you have to enable it on the datastores. Only if you want to prioritize a certain VM’s I/Os do you need to do additional configuration steps such as setting shares on a per VM basis. Yes, this can be a bit tedious if you have very many VMs that you want to change from the default shares value. But this only needs to be done once, and after that SIOC is up and running without any additional tweaking needed
The shares mechanism is triggered when the latency to a particular datastore rises above the pre-defined latency threshold seen earlier. Note that the latency is calculated cluster-wide. Storage I/O Control also allows one to tune & place a maximum on the number of IOPS that a particular VM can generate to a shared datastore. The Shares and IOPS values are configured on a per VM basis. Edit the Settings of the VM, select the Resource tab, and the Disk setting will allow you to set the Shares value for when contention arises (set to Normal/1000 by default), and limit the IOPs that the VM can generate on the datastore (set to Unlimited by default):
Why enable it?
The thing is, without SIOC, you could definitely hit this noisy neighbour problem where one VM could use more than its fair share of resources and impact other VMs residing on the same datastore. So by simply enabling SIOC on that datastore, the algorithms will ensure fairness across all VMs sharing the same datastore as they will all have the same number of shares by default. This is a great reason for admins to use this feature when it is available to them. And another cool feature is that once SIOC is enabled, there are additional performance counters available to you which you typically don’t have
What threshold should you set?
30ms is an appropriate threshold for most applications however you may want to have a discussion with your storage array vendor, as they often make recommendations around latency threshold values for SIOC
Problems
One reason that this can occur is when the back-end disks/spindles have other LUNs built on them, and these LUNs are presented to non ESXi hosts. Check out
KB 1020651 for details on how to address this and previous posts
and
General Rules for Processor Scheduling
Scheduling Issues
Performance enhancers for vSphere
vSphere has the ability to skip scheduling of idle processors. For example if a quad processor VM has activity on only 1 core, vSphere has the ability to schedule only that single core sometimes. A multi threaded app will likely be using most or all of its cores most of the time. If a VM has CPUs that are sitting idle a lot, it should be reviewed whether this VM actually needs the multiple processors
If your application is not multi-threaded, you gain nothing by adding cores to the VM and make it more difficult to schedule
2. Processor Skew
Guest OSs expect to see progress on all of their cores all of the time. vSphere has the ability to allow a small amount of skew whereby the processors need not be completely in sync but this has to be kept within reasonable limits
For a detailed description of how ESX(i) schedules VMs to processors please read
http://www.vmware.com/files/pdf/perf-vsphere-cpu_scheduler.pdf
Really useful ESXTOP Overview Chart of Performance Statistics courtesy of vmworld.net
