Tag Archives: Memory

Change Virtual Machine memory with VMware PowerCLI

Changing memory assigned to a virtual machine, you may think will be a quick 2 minute job. By default this task can only be performed whilst the virtual machine is powered off. If the guest vm supports hot add then this can be done when the machine is online.

To enable Hot add on a virtual machine you can follow this guide from VMware Change Memory Hot Add Settings in the vSphere Web Client

Turning a VM off during the business day might not go down to well with your customers/users. That leaves us with carrying out the change out of hrs, I’m your like me and prefer to keep your evening as your own rather than working.

The following can be saved as a ps1 script and scheduled to run out of hrs in a maintenance window. If you specify the email setting in the script an email will be generated once completed to notify that the change has been completed.

Prerequisite:

Install VMware vSphere PowerCLI, script has been tested with version 6 R1 available here vSphere PowerCLI 6.0 Release 1

All the variables are declared at the start of the script and prefixed with the dollar $ symbol.

##Created by DM 180915
##Task Change VM memory
##VM name
$VM2change = "test-server"
##Email Settings
$emailServer = "192.168.1.1"
$sender = "powercli@vsphere.local"
$recipients = "admin@vsphere.local"
##Load VMware PS plugin
Add-PSSnapin VMware.VimAutomation.Core
##Connect to vCenter
connect-viserver -server vcenter.vsphere.local -User administrator@vsphere.local -Password Password123
###########################Start- Custom Task #########################
$beforechange = (GET-VM -Name $VM2change|FT -auto MemoryGB|out-string)
##Stop VM
GET-VM -Name $VM2change| Stop-VMGuest -Confirm:$False
start-sleep -s 180
##Change Memory
GET-VM -Name $VM2change| set-vm -MemoryGB 28 -Confirm:$False
##Start VM
GET-VM -Name $VM2change| Start-VM -Confirm:$False
$afterchange = (GET-VM -Name $VM2change|FT -auto MemoryGB|Out-String)
##ping VM
start-sleep -s 120
$isalive= (Test-Connection -ComputerName $VM2change -count 1|Out-String)
###########################End- Custom task #########################
##Compose eMail and send
$body = @" 
Memory Before,$beforechange.
Memory After, $afterchange.
Is VM up??, $isalive
"@
send-mailmessage -from $sender -to $recipients -subject "VM Memory Change $VM2change" -Bodyashtml "$body" -smtpserver $EmailServer
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How to find VMware ESXi host memory layout

Whilst evaluating a customer’s environment to plan an infrastructure upgrade. I was tasked with finding out the current memory installed and slot layout of their ESXi hosts.

I stumbled across the following VMware KB which shows you how to dump the current hardware configuration. But with so much information this wasn’t easily readable across many hosts.

Determining how much RAM is installed in each slot on an ESXi host (1003587)

By using ‘smbiosDump’ command along with parsing the output with grep, this can be used to filter the results.

The following has been tested on Dell R410/R510/R720 ESXi servers running 5.5 and 6.0.

These commands will need to be run via the shell. To gain access to the an ESXi host remotely you need to make sure that SSH and the ESXi shell have been enabled. If you not sure how to enable these use the following VMware kb.

Using ESXi Shell in ESXi 5.x and 6.0 (2004746)

First of all I wanted to find out how many slots the server has and what the maximum amount of memory that can be installed.

 smbiosDump |grep -A 4 'Physical Memory Array'

sample output below
Physical Memory Array: #4096
Use: 0x03 (System memory)
Location: 0x03 (Motherboard)
Slots: 24
Max. Size: 1536 GB

This shows that 24 slots and a total of 1536 GB of memory can be installed. So this server can be filled with 24x64GB sticks of memory.

Secondly which slots have memory installed, along with type and size.

 smbiosDump |grep -A 12 'Memory Device' 

sample output below
Memory Device: #4352
Location: “DIMM_A1”
Manufacturer: “00AD00B300AD”
Serial: “XXXXXXXX”
Asset Tag: “XXXXXXXX”
Part Number: “HMT42GR7BFR4C-RD”
Memory Array: #4096
Form Factor: 0x09 (DIMM)
Type: 0x18 (DDR3)
Type Detail: 0x2080 (Synchronous, Registered)
Data Width: 64 bits (+8 ECC bits)
Size: 16 GB
Speed: 1866 MHz

The examples above filter the output using the grep command searching for specific string then listing the proceeding 12 lines, which contain the memory information required.