Check disk space and abort deployment if insufficient

A simple script to check disk space, and fail the deployment if it's below a certain threshold. Add to PreDeploy.ps1

#Disk Space predeployment check
#Create two variables in Deployment Manager:
# InstallationDriveToCheck = drive to check (with colon) eg. C:
# AbortIfDiskSpaceLessThanMB = amount of space which is needed to succeed, in MB eg. 1024 for 1GB
write-host "***Checking space on drive $InstallationDriveToCheck***"
write-host "Deployment will fail if less than $AbortIfDiskSpaceLessThanMB MB available"
$disk = gwmi win32_volume -Filter "driveletter='$InstallationDriveToCheck'"

[int64]$freespace = ($disk.Freespace) / 1024 / 1024 #convert to MB

if ($freespace -lt $AbortIfDiskSpaceLessThanMB)
{
    write-host "Drive $InstallationDriveToCheck has insufficient disk space! ($freespace MB)"
    exit -1
}
else
{
    write-host "Drive $InstallationDriveToCheck has $freespace MB  free, continuing..."
    exit 0
}