Deleting Folders filled with files doesn't free up space immediately

Question

When I delete a Folder using

DirectoryInfo.Delete(true)

the value for

DriveInfo.AvailableFreeSpace

stays nearly the same. For instance when I delete folders in a loop while checking availablefreespace I end up deleting gigabytes and gigabytes of data when it should have deleted less then a gigabyte.

//Delete in secondary storage
string secondaryRoot = Path.GetPathRoot(settings.SecondaryFeatureExtractDirectory);
DriveInfo secondaryDrive = new DriveInfo(secondaryRoot);
DirectoryInfo secondaryInfo = new DirectoryInfo(settings.SecondaryFeatureExtractDirectory);
while ((secondaryDrive.TotalSize - secondaryDrive.AvailableFreeSpace) / secondaryDrive.TotalSize * 100 < settings.DriveFreePercentage)
{
    logger.LogInformation("checkForCleanup before delete: {@Freespace}", secondaryDrive.AvailableFreeSpace);
    secondaryThresholdPassed = true;
    DirectoryInfo oldestDir = secondaryInfo.EnumerateDirectories().OrderBy(x => x.LastWriteTimeUtc).FirstOrDefault();
    if (oldestDir == null) break;
    oldestDir.Delete(true);
    logger.LogDebug("checkForCleanup deleted: {@DirectoryName}", oldestDir.FullName);
    logger.LogInformation("checkForCleanup after delete: {@Freespace}", secondaryDrive.AvailableFreeSpace);
    Thread.Sleep(1);

}

Is there any was around this using c# and dotnetcore?

Answer 1

All of the input values you are checking are integer types. Integer math does not include decimal portions of a number.

var di = //new DriveInfo("c");
    new
    {
        TotalSize = 255471906816L,
        AvailableFreeSpace = 125059747840L
    };

var ps = ((di.TotalSize - di.AvailableFreeSpace) / di.TotalSize) * 100;
Console.WriteLine(ps);  // 0
var ps2 = (int)((((double)di.TotalSize - di.AvailableFreeSpace) / di.TotalSize) * 100d);
Console.WriteLine(ps2);  // 51