Dell IDSDM not showing as a boot device Dell R640

Firstly I like these servers. They brought back the control panel/LCD on the front which is REALLY helpful when you are on the phone to someone remote. And the hardware you can run on them is amazing (2×28 core CPUs, 32TB RAM, NVDIMM support, M.2 support etc etc). 

However, one box I built for vSAN, caught me out.

No mater how may complete power downs, shutdowns, reboots and firmware upgrades I couldn’t get the Internal Dual SD Module (IDSDM) to show.

As you can see, no IDSDM
But it lists on Integrated Devices
However, from the DRAC it was there and happy. Although I couldn’t update its firmware.
I spoke to Dell to make sure I wasn’t going mental. They asked me to run through the ESXi install to see if ESXi could see it. And then, as if by magic, boom it worked. I could see the IDSDM along side my virtual optical drive and the other goodies you get from iDRAC

It appears it just needed a nudge and virtual media from iDRAC did it.
Hopefully this helps someone else who likes to configure their BIOS/ boot devices before they install.

This article and was done in coordination with Chris McChesney and Virtually Trivial.

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Reservations of VMs per host

Reservations are the devil.

The more you deep dive into reservations and resource pools the more you don’t want to touch them.

I wont go into great detail about the dangers as vFrank, Eric Sloof and Duncan Epping (to name but a few) have been telling us for years.

Basically unless you REALLY know what you are doing and you have a REALLY good reason to use them… Don’t.

However, back in the real world reservations are still being demanded by some vendors. Most notably anything to do with VOIP. Which is understandable as you don’t want these guys fighting for resources. I will say though some of the numbers they ask for can be eye watering.

One problem with reservations is that it can be quite difficult how much non reserved CPU MHz is actually left on a single host. vCenter will show you for the cluster but it doesn’t dive down to each host.

So you can have a scenario where you have a host with 10 VMs. 5 of them have reservations for half the CPU between them and the rest have none.

When the reservation VMs are doing nothing the CPU scheduler will allow the other VMs to use those cycles.

But.. what happens when the host gets busy. This is when things get tricky. If the reservation VMs are using 50% of the CPU then the other 5 hosts have to fight for the rest. If the reservations set are not high enough, the reservation VMs will ask for additional resources as well. Then you have to factor in hypervisor overhead for things like VSAN, iSCSI etc the list goes on.

Using DRS for VOIP things can be a no no or the host itself may not even be licensed for it.

So, what can you do to see how much actual free cycles are on each host?

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Updating ESXi Advanced Settings with Menu Driven PowerCLI

This code will create menus for you to update Advanced Settings (or edit it to do other things… it’s the menus that are most important) for your ESXi hosts. It connects to vCenter, creates a menu of clusters to select from, creates a menu of hosts to select from and then executes the change. It puts the host in maintenance mode, updates the value and reboots the host.

The code runs past the edge of the page, but there are controls on the below widget to expand it so you can see all of it. 🙂

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vCenter 6.7 Update 3 HA with DDNS – Disable DDNS on vCenter

As it stands today (11/11/2019), vCenter 6.7U3 has been released with a new DDNS “feature” that seems to be creating an issue when leveraging vCenter HA. The issue is that when vCenter updates DNS, it sends both the management IP and the HA IP. The HA IP should really never be seen by the end user. Since both IPs are updated in DNS via DDNS, you get a round-robin situation for the name that you have allocated to your vCenter appliance.

This will take you through updating vCenter so it doesn’t do DDNS and hence does not create two DNS entries for your vCenter server. Having said that, you will have to create a static DNS entry for your vCenter server (which is the normal operation when deploying vCenter anyway).

Please see the Release Notes to read more on the DDNS feature.

Disable DDNS on vCenter

  1. We are going to need to SSH into your vCenter server. 
  2. Type the following to remove the cron job. Feel free to back the file up.

    cd /etc/cron.d/

    rm -f dns_update.cron

  3. We now have to deal with a python script that runs. Type the following:

    ps -eaf | grep ddns

  4. This will give you a PID for the following:



  5. For this example, we are grabbing the 4431 PID and executing the following:

    kill -9 4431

  6. Let’s validate that we have killed it.

    ps -eaf | grep ddns

  7. Just make sure the ddns.py script isn’t running.
  8. Now we need to do an edit.

    cd /usr/lib/applmgmt/support/scripts/

    vi prestart-applmgmt.sh

  9. Since you are in vi, lets hit the / key and type: DDNS
  10. You will find the following lines that you need to comment out. Please see the below snippet of what needs to be commented:



  11. Note that we’ve added a # in front of each of the lines we no longer want to run.

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