Laura Slot Vmware
By Duncan Epping, Principal Architect, VMware
Yesterday I received a question on twitter:
May 19, 2020 In deze video vertelt Laura Slot, Account Executive Local Government bij VMware, naar welke vForum 2020 sessie hij het meest uitkijkt. Registreer hier: https. 835 Followers, 687 Following, 3 Posts - See Instagram photos and videos from Laura (@laura.vm). 835 Followers, 687 Following, 3 Posts - See Instagram photos and videos from Laura (@laura.vm).
Hi, to settle an argument in the office, if no reserves are in place, does number of vCPU’s affect slot size in vSphere 4? Thx 🙂
First of all, what is a slot? The availability guide explains it as follows
A slot is a logical representation of the memory and CPU resources that satisfy the requirements for any powered-on virtual machine in the cluster.
In other words a slot is the worst case CPU and Memory reservation scenario for any given virtual machine in a cluster. This slot is used when Admission Control is enabled and “Host Failures Tolerates” has been selected as the admission control policy. The total amount of available resources in the cluster will be divided by the slot size and that dictates how many VMs can be powered on without violating availability constraints. Meaning that it will guarantee that every powered on virtual machine can be failed over.
As said this slot is dictated by the worst case reservation for CPU and Memory. Prior to vSphere 4.0 we used the number of vCPUs to determine the slotsize for CPU as well. But we do not use vCPUs anymore to determine the slot size for CPU. The slotsize for CPU is determined by the highest reservation or 256MHz (vSphere 4.x and prior) / 32MHz (vSphere 5) if no reservation is set.
However, vCPUs can have an impact on your slot… it can have an impact on your memory slotsize. If no reservation is set anywhere HA will use the highest Memory Overhead in your cluster as the slot size for memory. This is where the amount of vCPUs come in to play, the more vCPUs you add to a virtual machine the higher will your memory overhead be.
I guess the answer to this question is: For CPU the number of vCPUs does not impact your slotsize, but for memory it may.
We are doing a forklift upgrade of our servers, in order to do so, I would like to connect my esx hosts to both fabrics for a while so I can transfer the VM's over that network and not the front end ethernet network. Because I don't want to make changes to the legacy Fibre, and I don't want to connect the fabrics more than I must, I will disconnect the redundant fibre cable from each ESX host and connect it to the new fibre. Here are my steps.First go into vcenter, identify the correct HBA WWN, I just use the last octet, so I want to re-use '86', so that is the HBA I am going to disconnect from the existing Fibre.
Then Go into the Properties of each Datastore and click 'Manage Paths', change the path selection policy to 'Fixed' (so we can control what path the Host is using to access the current storage), Click 'Change', click the status of the current path you wish to keep (not using 86), and click Preferred. After that, click the paths that 86 is using, and choose Disable. It should then look something like below, you can see the Adapter listed after the Path is chosen.
Click Close and repeat for all datastores. You also can verify/do this work from the Configuration/Storage Adapter page, which will look something like below, Note that we are looking at HBA2 (86), Under 'Paths' and you can see status is Disabled.
After disabling all of the paths under each datastore, you may still have some paths left, those are just the connections to the array, but not actually a connection to a LUN. You can disable those if you choose, I do because I try to never leave anything to chance. At this point this HBA is no longer in use and is ready to be re-used to connect to the new Fibre.
Laura Slot Vmware Games
In my case, I am using an HP server with HBA's installed into PCIe slots. My question is, which HBA is mapped to which PCIe Slot (I don't want to disconnect the wrong one since I just removed redundancy). I am using ESXi 5.x, so I have enabled SSH for troubleshooting. I tried logging into iLo, however it did not have PCIe slot card information, so I decided to go right twards the horses mouth so to speak and have SSH'd into my server and ran the following command:esxcli hardware pci list
but that gave me alot of information I couldn't use, so then I tried:
Laura Slot Vmware Software
lspciLaura Slot Vmware Support
which gave me:
000:067:00.0 Serial bus controller: QLogic Corp ISP2432-based 4Gb Fibre Channel to PCI Express HBA [vmhba1]
Laura Slot Vmware System
000:070:00.0 Serial bus controller: QLogic Corp ISP2432-based 4Gb Fibre Channel to PCI Express HBA [vmhba2]This is perfect information, because the HP Quickspecs for the DL385G2 has the following info: