PowerShell - Azure Delete Reserved disks over 90 days - azure

Question

i am facing a mission in my work and she goes like this:
We have disks in our Azure account that they are attached to stopped and stopped(deallocated) vms. if am saying right they called Reserved disks.
The problem that we are still charged for this disks, i need your help with a PowerShell Script to look for this disks over xx days and than delete them.
my script for now looks like this.. please anyone that expert in PowerShell can help me here?
*** UPDATE - The mission i got have changed to list all the vms that are in status deallocated over xx days and than remove the disks that related to them.
# Get orphan managed disks
$managedDisks = Get-AzDisk
foreach ($md in $managedDisks) {
if (($md.ManagedBy -eq $null) -and ($md -notlike '*-ASRReplica')) {
$md | Remove-AzDisk -Force -verbose
}
}
Thank you all !!!

Answer 1

Per my understanding, you already get the way to filter all managed disks that have not been appended to a VM. And now, you want to know how to filter all managed disks that have not been used for 30 days.
For this requirement, we can query disk metrics: if a disk has been used in 30 days, there should be some metrics data(i,e read bytes and write bytes):
and if it has not been used, its metrics data in this period of time should be empty. So we can use PowerShell below to check:
#check disk read and write metrics log for each hour in past 30 days
$now = Get-Date -AsUtc
$m = Get-AzMetric `
-ResourceId '<managed disk resource ID>' `
-StartTime $now.AddDays(-30) `
-EndTime $now `
-TimeGrain 01:00:00 `
-MetricName 'Composite Disk Read Bytes/sec','Composite Disk Write Bytes/sec'
$readMetricsRecord = $m[0].Data
$writeMetricsRecord = $m[1].Data
if($readMetricsRecord.length -eq 0 -and $writeMetricsRecord.length -eq 0){
echo 'this disk has no usage record'
}else{
echo 'this disk has been used'
}

Answer 2

sharing with you the script guys , Get the vms in deallocated state over X days than , if they have a disk that is over X GB tag the vm and the disk .
$ids = New-Object System.Collections.ArrayList
$mergedTags = #{"Candidate"="Delete Me"}
$vms = (Get-AzVM -Status)
foreach ($vm in $vms ) {
$getStatuses = Get-AzVM -ResourceGroupName $vm.ResourceGroupName -Name $vm.Name -Status
$getTodaysDate = Get-Date
$ts = New-TimeSpan -Start (($getStatuses.Statuses).Time).DateTime -End $getTodaysDate
[bool]$flag = 0
if (($vm.PowerState -eq "VM deallocated") -AND ($ts.Days -gt 30)) {
$ids.Add($vm.Id)
foreach ($disk in $getStatuses.Disks.Name) {
$diskSize = Get-AzDisk -ResourceGroupName $vm.ResourceGroupName -Name $disk
if ($diskSize.DiskSizeGB -gt 50) {
$flag = 1
$ids.Add($diskSize.Id)
if ($flag = 1) {
Update-AzTag -ResourceId $vm.Id -Tag $mergedTags -Operation Merge
Update-AzTag -ResourceId $diskSize.Id -Tag $mergedTags -Operation Merge
}
}
}
}
}
}