Configuring a syslog folder is convenient for troubleshooting ESXi. But it’s a pain you-know-where to configure manually across all your ESXi servers. Luckily, PowerCLI can help out. This script creates a folder on the local datastore and configures ESXi to write the syslog in that folder.
Enjoy!
Hugo

#Folder name you like
$syslogFolderName = "syslog"

#Connect to vCenter
Connect-VIServer vcenter.domain.local

#Loop through hosts
ForEach ($vmhost in Get-VMHost)
{
#Get only the first part of the FQDN (only if you used the FQDN to add the ESX server to vCenter)
$hostname = $vmhost.name.split(".")[0].ToUpper()

#Local datastore name (equal to hostname in my case)
$datastorename = $hostname

#Make the local datastore accessible as a PSdrive
New-PSDrive -Name $hostname -Root \ -PSProvider VimDatastore -Datastore (Get-Datastore $datastorename) -Scope global

#Access the new PSDrive
Set-Location $hostname":"

#Create the syslog folder
New-Item $syslogFolderName -ItemType directory

#Set the advanced parameter to configure the syslog on the local datastore
$value = "[$datastorename] $syslogFoldername/$hostname.log"
Set-VMHostAdvancedConfiguration -VMHost $vmhost -Name "Syslog.Local.DatastorePath" -Value $value

#Cleanup
Set-Location $PSHOME
Remove-PSDrive $hostname
Clear-Variable hostname -ErrorAction SilentlyContinue
Clear-Variable datastorename -ErrorAction SilentlyContinue
Clear-Variable value -ErrorAction SilentlyContinue
}

#Disconnect from vCenter
Disconnect-VIServer -confirm:$false