Powershell Plus or Minus Comparison Operator (Fuzzy Logic)? - windows

Question

So let me tell you what I'm trying to do here. Our SolarWinds alerts report on disk capacity as read by Windows, not the Virtual Machine vDisk size setting. What I'm trying to do is match the size so that I can find the correct vDisk and report on its datastore free space to determine whether or not we can add more.
Here's the problem, the GB number never matches between Windows and VMWare. Say the disk has a 149.67 capacity as reported by Windows, well the VMWare setting is 150, or 150.18854, or anything of that sort. I cannot find the vdisk without knowing the exact number, but theoretically I could find it if I could just say, have a comparison operator that had some breathing room, like plus or minus 1 or even 0.5. So for example:
Get-HardDisk -Vm SERVERNAME | Where-Object {
$_.CapacityGB -lt $size + 0.5 -and
$_.CapacityGB -gt $size - 0.5
}
This doesn't work though, for whatever reason. I need something similar to this. Any ideas?
UPDATE: Turns out to be user error, I was experimenting with the wrong number when testing the command. I thought it was the syntax, it was the number I was using itself.

Answer 1

So because I managed to answer my own question I thought I'd post a script for achieving this here. Note that you will need to have a txt file with a comma separated servername and capacity. You could probably modify this to do many other things with VMWare data gathering if you wanted. In the end you'll need to know which columns are which and import to Excel as comma delimited.
Most the variables are decimal values.
Also note that I have no yet figured out a way to programatically deal with the discovery of multiple matching disks.
$serverlist = Get-Content "./ServerList.txt"
$logfile = "./Stores.txt"
remove-item "./Stores.txt"
Function LogWrite {
Param (
[string]$srv,
[string]$disk,
[string]$store
)
Add-Content $logfile -value $srv","$disk","$store
}
foreach ($item in $serverlist){
$store = "Blank"
$disk = "Blank"
try {
$server,$arg = $item.split(',')
$round = [math]::Round($arg,0)
$disk = get-harddisk -vm $server | where-object{$_.CapacityGB -lt ($round + 2) -and $_.CapacityGB -gt ($round - 2) }
if ([string]::IsNullOrEmpty($disk)){
$disk = "Problem locating disk."
$store = "N/A"
continue
}
if ($disk.count -gt 1) {
$disk = "More than one matching disk."
$store = "N/A"
} else {
$store = get-harddisk -vm $server | where-object{$_.CapacityGB -lt ($round + 2) -and $_.CapacityGB -gt ($round - 2) } | Get-Datastore | %{ "{0},{1},{2}" -f $_.Name,[math]::Round($_.FreeSpaceGB,1),[math]::Round($_.CapacityGB,1) }
}
}
catch {
$disk = "Physical"
$store = "N/A"
}
LogWrite $server $disk $store
}