Capacity and Efficiency per VM

This (probably poorly written) Powershell code will go grab all the VVols on a SolidFire system, group them by VM and then give you a read out of allocated and consumed capacity. It also reports on the overall efficiency of each VM.

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#Connect to SolidFire system if no connection already exists
if(!$sfconnection){
Connect-SFCluster 172.27.40.200 -Username admin -Password solidfire | Out-Null
}

#Misc stuff
$separator = ".","_"

#Get a list of all the VVols and their stats
$VVols = Get-SFVirtualVolume -Details $true

#Group VVols by VM
#The VMW_VmID uniquely identifies the VVols associated with a VM
#Get list of unique VMW_VmID

foreach ($VmID in $VVols.metadata.VMW_VmID | Sort | Get-Unique) {

    #Get a unique VM object
    $VMObject = $VVols | select VirtualVolumeID,VolumeInfo,Metadata | where-object {$_.Metadata.VMW_VmID -match $VmID}
    $VMName = $VMObject.metadata.VMW_VVolName 
    $NumVVols = $VMObject.count
    
    $VMVVolStats = $VMObject.VolumeInfo.VirtualVolumeID | Get-SFVolumeStatsByVirtualVolume
    $VMVolEfficiencies = $VMObject.VolumeInfo.VolumeID | Get-SFVolumeEfficiency
      
    #Do some math for Agreegate capacity
    foreach ($VMVVolStat in $VMVVolStats) {
        $VMAllocatedCapactiy += $VMVVolStat.volumesize 
        $VMConsumedBlocks += $VMVVolStat.NonZeroBlocks
    }    
        
    #Create estimated efficiency per volume
    For ($i=0; $i -lt $VMVVolStats.Count; $i++) {

    #Catch if there is a 0 compression or deduplication number, if so set to 1
    If ($VMVolEfficiencies[$i].Deduplication -eq "0") { 
        $VMVolEfficiencies[$i].Deduplication = 1
    }
    If ($VMVolEfficiencies[$i].Compression -eq "0") {
        $VMVolEfficiencies[$i].Compression = 1
    }

    $VMVVolEfficiency = $VMVolEfficiencies[$i].Deduplication * $VMVolEfficiencies[$i].Compression
    $VMDiskEffectiveSize = (($VMVVolstats[$i].NonZeroBlocks * 4096) /1gb) / $VMVVolEfficiency
    $TotalVMEffective += [math]::Round($VMDiskEffectiveSize,2)                
    }

    #Turn blocks into bytes (not quite as exciting as water to wine)
    $VMConsumedCapacity = [math]::Round($VMConsumedBlocks * 4096 /1gb,2)
    $VMEffectiveEfficiency = [math]::Round($VMConsumedCapacity / $TotalVMEffective,2)

    #Total Counters
    $AllVMConsumed += $VMConsumedCapacity
    $AllVMEffective += $TotalVMEffective
    $AllEfficiency = [math]::Round(($AllVMConsumed / $AllVMEffective),2)

    #Note, all the capacity values are in GiB, not GB
    Write-Host "`nVM Name: $($VMName.split($separator) | select -first 1)" -ForegroundColor DarkGray
    Write-Host "Number of VVols: $NumVVols" -ForegroundColor Green
    Write-Host "VM Allocated GiB: $($VMAllocatedCapactiy /1gb)" -ForegroundColor Green
    Write-Host "VM Consumed GiB: $VMConsumedCapacity" -ForegroundColor Green
    Write-Host "VM Effective GiB: $TotalVMEffective" -ForegroundColor Green
    Write-Host "VM Effective Efficiency: $VMEffectiveEfficiency" -ForegroundColor Green

    #Clear out counters
    $VMAllocatedCapactiy = 0
    $VMConsumedBlocks = 0
    $TotalVMEffective = 0
    $VMDiskEffectiveSize = 0
    $TotalVMEffective = 0
    $VMConsumedCapacity = 0
    $VMEffectiveEfficiency = 0
}
Write-Host "`nTotal Consumed GiB Used by VMs:"  $AllVMConsumed
Write-Host "Total Effective GiB Used by VMs:" $AllVMEffective
Write-Host "Total Effective Efficiency:" $AllEfficiency

I’ll just come right out and say that the efficiency number really isn’t all that useful by itself. The reason being that the GetVolumeEfficiency call looks at a volume in isolation. This means it only reports the efficiency within the individual volumes, not across volumes. Practically that means the reported number is a worst case scenario.

However, it is useful in the sense that it provides a pretty decent expected ratio among a set of VMs. In the example above, I can see that my vra-2012r2 template reduced 1.91x and my vra-sql2014 template reduced 1.62x – a difference of ~ 15%. Generally speaking that means I can expect to get roughly 15% better efficiency rates with the vra-2012r2 VMs vs the vra-SQL2014 VMs. That might be useful information to have.

To test if this holds in a deployment, I created two storage containers (vra-2012r2 and vra-SQL2014) and deployed 50 VMs to each from the respective VM templates.

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This allows SolidFire to report the efficiency for all the VMs in those two storage containers independently so we can see how well we dedupe/compress across the VMs in the same storage container. Given the numbers reported per-VM earlier I would expect the vra-2012r2 storage container to get roughly 15% better numbers.

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So we did, in fact, get better efficiency for the vra-2012r2 VMs and the difference in efficiency is ~20% which is in the ball park Smile After 24 hours the the difference was ~17%, almost exactly matching the original difference in the templates. So, not an exact science, but useful for general sizing estimates.

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