The RescanHBA and RescanVmfs are slow and the system will execute them sequentially.
There is not a lot that can be improved speed-wise.
And this is not a PowerCLI thing, as the 2nd snippet should show.
The fact the methods (see 2nd snippet), don't have a _Task suffix (run in the background) is telling.
The 1st method to potentially win some execution time, is to run the scans in parallel.
But there you will notice that they are still executed in sequence.
$job = {
param($session,$esx)
Connect-VIServer -Server $session.Name -Session $session.Sessionid
Write-Host " Rescan $($esx.Name)"
$m = Measure-command {$ScanResults += Get-VMHostStorage -VMHost $esx.Name -RescanAllHba -RescanVmfs}
Write-Host " Get-VMHostStorage for $($esx.Name) took $($m.TotalSeconds) seconds to complete."
}
if ($ReScan) {
write-host ("Forcing hosts to rescan storage.")
$ScanResults = @()
$h = Measure-Command {
$Hosts = Get-VMHost |
Where-Object {($_.ConnectionState -notlike '*dis*') -and ($_.ConnectionState -notlike '*not*')} |
Sort-Object -Property Name
}
Write-Host " Getting host list: Get-VMHost took $($h.TotalSeconds) seconds to complete."
$ts = Measure-Command {
$jobs = @()
$Hosts | ForEach-Object {
$jobs += Start-Job -ScriptBlock $job -ArgumentList $global:defaultviserver,$_ -Name scan
}
Wait-Job -Job $jobs
Receive-Job -Job $jobs
}
Write-Host " Get-VMHostStorage for all $($Hosts.count) hosts took $($ts.TotalSeconds) seconds to complete."
}
Another way to improve the execution time is to call the vSphere methods directly.
But this is still slow, and you only see a very small improvement (any potential PowerCLI overhead).
if ($ReScan) { write-host ("Forcing hosts to rescan storage.")
$ScanResults = @()
$h = Measure-Command {
$Hosts = Get-VMHost |
Where-Object {($_.ConnectionState -notlike '*dis*') -and ($_.ConnectionState -notlike '*not*')} |
Sort-Object -Property Name
}
Write-Host " Getting host list: Get-VMHost took $($h.TotalSeconds) seconds to complete."
$ts = Measure-Command {
$Hosts | ForEach-Object {
Write-Host " Rescan $($_.Name)"
$m = Measure-command {
$storSys = Get-View -Id $_.ExtensionData.ConfigManager.StorageSystem
$storSys.RescanAllHba()
$storSys.RescanVmfs()
}
Write-Host " Get-VMHostStorage for $($_.Name) took $($m.TotalSeconds) seconds to complete."
}
}
Write-Host " Get-VMHostStorage for all $($Hosts.count) hosts took $($ts.TotalSeconds) seconds to complete."
}
In conclusion, no big time gains possible.
