BACKGROUND
Our company is leveraging an IO density-based storage tiering solution, and the challenge for we as ESX admins is how to teach the hypervisor to grant access to IOps to a LUN with respect to the size of the VMDK. A few options for this, but none really as viable for a service provider as VMDK IO limits.
The following script applies IO limits to every VMDK based on the position of a tier string indicator of the housing datastore name. Different strings, IO density levels, etc. can be customized to your needs. I have the line that actually applies the IO limits commented out, so it is safe for execution in your environment. It will generate a report detailing what it found, which can be helpful in finding any outliers.
SCRIPT
$VCServer = "VCServer01"
$CsvExport = "c:\tmp\SetIOLimit.csv"
Connect-VIServer $VCServer
$report = @()
$VMs = Get-VM
foreach ($Vm in $Vms) {
$VmHdds = Get-HardDisk -VM $Vm | select Name, ExtensionData, Filename, CapacityKB
foreach ($VmHdd in $VmHdds) {
$row = "" | select VmName, HddName, ScsiID, Datastore, Tier, IODensity, CapacityGB, CurrentIOLimit, CalculatedIOLimit, IOLimitCorrect
$row.VmName = $Vm.Name
$row.HddName = $VmHdd.Name
$row.ScsiID = $([string]$VmHdd.extensiondata.controllerkey).substring(3,1) +":"+ $([string]$VmHdd.extensiondata.unitnumber)
$row.Datastore = $($VmHdd.Filename.TrimStart("[")).split("]")[0]
$row.Tier = $row.Datastore.Split("-")[5] ### Our datastore naming convention includes the tier indicator at the 6th delmimited location (i.e. xr-012-n-s-hb-brz-1581-004)
switch ($row.Tier) {
"brz" {$row.IODensity = .03}
"slv" {$row.IODensity = .4}
"gld" {$row.IODensity = 3.2}
"t1" {$row.IODensity = 3.2}
"plt" {$row.IODensity = 20}
default {$row.IODensity = "Invalid DS name or tier identifier"}
}
$row.CapacityGB = $VmHdd.capacitykb / 1024 / 1024
$row.CurrentIOlimit = $VmHdd.ExtensionData.StorageIOAllocation.limit
$row.CalculatedIOLimit = [int]($row.IODensity * $row.CapacityGB)
if ($row.CurrentIOLimit -eq -1) {$row.IOLimitCorrect = "No IO Limit Set"}
elseif ($row.CurrentIOLimit -gt $row.CalculatedIOLimit) {$row.IOLimitCorrect = "Too High"}
elseif ($row.CurrentIOLimit -lt $row.CalculatedIOLimit) {$row.IOLimitCorrect = "Too Low"}
else {$row.IOLimitCorrect = "Just Right"}
$report += $row
### Uncomment the following and this script will set the IO Limit for VMDKs during execution
# if ($row.IOLimitCorrect -ne "Just Right") {$Vm | Get-VMResourceConfiguration | Set-VMResourceConfiguration -Disk $VmHdd -DiskLimitIOPerSecond $row.CalculatedIOLimit}
}
}
$report | Export-Csv $CsvExport -NoTypeInformation
Disconnect-VIServer $VCServer -Confirm:$false -Force:$true
SAMPLE OUTPUT
| VmName | HddName | ScsiID | Datastore | Tier | IODensity | CapacityGB | CurrentIOLimit | CalculatedIOLimit | IOLimitCorrect |
| XRDCLPXTMGT01 | Hard disk 1 | 0:00 | xr-004-p-s-st-brz-1581-003 | brz | 0.03 | 80 | -1 | 2 | No IO Limit Set |
| XRDCWPTRMCTX07E | Hard disk 1 | 0:00 | xr-004-p-s-st-slv-1581-004 | slv | 0.4 | 40 | -1 | 16 | No IO Limit Set |
| XRDCWPTRMCTX07E | Hard disk 2 | 0:01 | xr-004-p-s-st-slv-1581-018 | slv | 0.4 | 75 | -1 | 30 | No IO Limit Set |
| XRDCWPWEBTAR01B | Hard disk 1 | 0:00 | xr-004-p-s-st-slv-1581-004 | slv | 0.4 | 40 | -1 | 16 | No IO Limit Set |
| XRDCWPWEBTAR01B | Hard disk 2 | 0:01 | xr-004-p-s-st-slv-1581-018 | slv | 0.4 | 50 | -1 | 20 | No IO Limit Set |
