Throttling a VM's IOPS - vSphere 6

By default there is no disk I/O throttling setup within vSphere - in order to get an idea of how many IOPS the machine is hitting we should firstly use esxtop to provide the information:

SSH into the ESXI host >> run the 'esxtop' command >> press the 'v' key to go into the VM view.

You can then confirm the IOPS by observing the CMDS/s column.

Dependent on your disk setup you could also make use of an IOPS calculator to give you an estimate of what kind of IPOS you should be expecting:

http://www.thecloudcalculator.com/calculators/disk-raid-and-iops.html

Once we have a figure in mind we should proceed to the vSphere Web Client >> VMs >> Right-hand click on the VM in question and select 'Edit Settings' >> Expand the relevent virtual hard drive(s) and enter you desired figure in the "Limit - IOPs" textbox.

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How to check the queue depth of a storage controller using ESXTOP

 From http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1027901

To identify the storage adapter queue depth:

1. Run the esxtop command in the service console of the ESX host or the ESXi shell (Tech Support mode). For more information, see Using Tech Support Mode in ESXi 4.1 and ESXi 5.0 (1017910) or Tech Support Mode for Emergency Support (1003677) .
2. Press d.
3. Press f and select Queue Stats.
4. The value listed under AQLEN is the queue depth of the storage adapter. This is the maximum number of ESX VMKernel active commands that the adapter driver is configured to support.

To identify the storage device queue depth:

1. Run the esxtop command in the service console of the ESX host or the ESXi shell (Tech Support mode). For more information, see Using Tech Support Mode in ESXi 4.1 and ESXi 5.0 (1017910) or Tech Support Mode for Emergency Support (1003677).
2. Press u.
3. Press f and select Queue Stats.
4. The value listed under DQLEN is the queue depth of the storage device. This is the maximum number of ESX VMKernel active commands that the device is configured to support.

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My collection of useful Powershell commands

The below is (or rather will be) a compilation of powershell commands that have come in handy for myself during day to day operations.

Ensure all users in a specific OU have thier accounts set to "Password Never Expires":

Get-AdUser -Filter * -SearchBase "OU=myou,DC=my,DC=domain" -Server dc01 | Set-ADUser -PasswordNeverExpires $true -Credential administrator

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Error: A binding for this client already exists.

When attempting to add a reservation into a Cisco 1841 I encountered the following error message:

A binding for this client already exists.

when running:

client-identifier 0100.0111.001e.48

To resolve firstly identify which IP address the MAC address is assosiated with - this can be performed with:

show ip dhcp binding

Identify the assosiated IP and then simply run the following command to remove the binding:

clear ip dhcp binding <ip-address>

You should now be able to run the client-identifier command again.

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Setting up a reverse proxy for several websites with IIS and TMG 2010

Firstly launch the Forefront TMG Console and go to the "Firewall Policy" node and select "Publish Web Sites" on the Tasks" navigation window on the far left.

In the wizard give the rule name something like "Reverse Proxy" >> Next >> Allow >> Select "Publish multiple Web sites" >> Add your desired site.

The wizard will also ask you to create a new 'Listener' - assign or add an additional IP address to your 'External' adapter.

Make the appropriate DNS entries into your DSN system and proceed by going to IIS and setting up our reverse proxy:

We will need to download the 'URL Rewrite' module for IIS (supported on IIS 7.0+) from the following URL:

http://www.iis.net/downloads/microsoft/url-rewrite

and also the 'Application Request Routing' extension available from:

http://www.iis.net/downloads/microsoft/application-request-routing

Once installed go to IIS Manager >> Server >> 'Application Request Routing' >> 'Server Proxy Settings...' >> Ensure 'Enable Proxy' is ticked.

Once installed launch the IIS Manager >> Create a New Website >> URL Rewrite >> Reverse Proxy and enter the relevent information.

Finally restart your site and test.

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Performing a test DR recovery of a virtual machine with vSphere Replication

Unless you are using vSphere Replication with Site Recovery Manager you will not be able to perform a 'test recovery' (i.e. recover the VM while the source site/VM is still active/online). The process you could follow in case you would like to keep your primary site online is as follows:

1. Perform Recovery using the second option (Recover with latest available data). In this way you would not need to power off source VMs and your primary site will be online.

2. After recovery is complete, stop the replications (which will be in Recovered state)

3. Power off recovered VMs, unregister them from VC inventory, but keep the disk files intact.

4. Manually configure all replications using the disks that were left over as initial seeds. This will cause only changes to be synced.

Source: https://communities.vmware.com/message/2409693

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