// HUGE REFACTORING NEEDED
private void tryMigrate(MetadataServer md)
{
Dictionary<string, int> sumAccesses = new Dictionary<string, int>();
int averageAll = 0;
foreach (string di in md.DataServersInfo.Keys)
{
int dataAccess = 0;
if (md.DataServersInfo[di] != null)
{
foreach (string file in md.DataServersInfo[di].GetNumberAccesses().Keys)
{
dataAccess += md.DataServersInfo[di].GetNumberAccesses()[file];
}
if (md.DataServersInfo[di].GetNumberAccesses().Count != 0)
{
sumAccesses.Add(di, dataAccess);
}
else
{
sumAccesses.Add(di, 0);
}
}
}
int aux = 0;
foreach (string di in sumAccesses.Keys)
{
aux += sumAccesses[di];
}
averageAll = (int)(aux / sumAccesses.Count);
int min = averageAll - Util.IntervalAccesses(md.Percentage, averageAll);
int max = averageAll + Util.IntervalAccesses(md.Percentage, averageAll);
List<string> OverloadServers = new List<string>();
List<string> UnderloadServers = new List<string>();
foreach (string s in sumAccesses.Keys)
{
if (sumAccesses[s] >= max)
{
OverloadServers.Add(s);
}
else if (sumAccesses[s] <= min)
{
UnderloadServers.Add(s);
}
}
if (OverloadServers.Count != 0 && UnderloadServers.Count != 0)
{
string mostOverloadedServer = "";
string mostUnderloadedServer = "";
long maxFiles = Int64.MinValue;
long minFiles = Int64.MaxValue;
foreach (string s in OverloadServers)
{
if (md.DataServersInfo[s].GetTotalAccesses() > maxFiles && md.DataServersInfo[s].GetNumberAccesses().Count > 1)
{
maxFiles = md.DataServersInfo[s].GetTotalAccesses();
mostOverloadedServer = s;
}
}
string mostAccessedfile = "";
long maxAccesses = Int64.MinValue;
if (mostOverloadedServer == null)
return;
foreach (string f in md.DataServersInfo[mostOverloadedServer].GetNumberAccesses().Keys)
{
if (md.DataServersInfo[mostOverloadedServer].GetNumberAccesses()[f] > maxAccesses)
{
maxAccesses = md.DataServersInfo[mostOverloadedServer].GetNumberAccesses()[f];
mostAccessedfile = f;
}
}
while (UnderloadServers.Count != 0)
{
mostUnderloadedServer = "";
minFiles = Int64.MaxValue;
foreach (string s in UnderloadServers)
{
if (md.DataServersInfo[s].GetTotalAccesses() < minFiles)
{
minFiles = md.DataServersInfo[s].GetTotalAccesses();
mostUnderloadedServer = s;
}
}
string secondMostAccessedfile;
maxAccesses = Int64.MinValue;
List<string> previousFiles = new List<string>();
int i = md.DataServersInfo[mostOverloadedServer].GetNumberAccesses().Count;
while (i != 0)
{
secondMostAccessedfile = null;
foreach (string f in md.DataServersInfo[mostOverloadedServer].GetNumberAccesses().Keys)
{
if (f != mostAccessedfile && !previousFiles.Contains(f))
{
if (md.DataServersInfo[mostOverloadedServer].GetNumberAccesses()[f] > maxAccesses &&
(!md.OpenFiles.ContainsKey(f)))
{
maxAccesses = md.DataServersInfo[mostOverloadedServer].GetNumberAccesses()[f];
secondMostAccessedfile = f;
}
}
}
if (secondMostAccessedfile != null)
{
if (!md.DataServersInfo[mostUnderloadedServer].GetNumberAccesses().ContainsKey(secondMostAccessedfile))
{
Console.WriteLine("Migration: File " + secondMostAccessedfile + " from " + mostOverloadedServer + " to " + mostUnderloadedServer);
md.getMigratingList().Add(secondMostAccessedfile);
md.getMigration().Reset();
Metadata meta = md.Files[secondMostAccessedfile];
string readServer = md.LiveDataServers[mostOverloadedServer];
string writeServer = md.LiveDataServers[mostUnderloadedServer];
IDataServer readDataServer = (IDataServer)Activator.GetObject(typeof(IDataServer), readServer);
IDataServer writeDataServer = (IDataServer)Activator.GetObject(typeof(IDataServer), writeServer);
File file = readDataServer.Read(secondMostAccessedfile, "default");
string toWrite = Util.ConvertByteArrayToString(file.Content);
byte[] content = Util.ConvertStringToByteArray(file.Version.ToString() + (char)0x7f + toWrite);
writeDataServer.Write(secondMostAccessedfile, content);
readDataServer.RemoveFromDataInfo(secondMostAccessedfile);
string command = string.Format("UPDATE {0} {1}", writeServer, secondMostAccessedfile);
meta.AddDataServers(writeServer);
meta.DataServers.Remove(readServer);
md.ServersLoad[mostOverloadedServer]--;
List<object> context = new List<object>();
context.Add(md);
context.Add(command);
md.Log.Append(command);
ThreadPool.QueueUserWorkItem(AppendToLog, context);
md.getMigration().Set();
md.getMigratingList().Remove(secondMostAccessedfile);
return;
}
else
{
previousFiles.Add(secondMostAccessedfile);
maxAccesses = Int64.MinValue;
i--;
}
}
else
{
UnderloadServers.Remove(mostUnderloadedServer);
break;
}
}
}
}
}
// Project API
public override Metadata Open(MetadataServer md, string clientName, string filename)
{
if (md.getMigratingList().Contains(filename))
{
md.getMigration().WaitOne();
}
// If already opened by one client
if (md.OpenFiles.ContainsKey(filename))
{
List<string> clientsList = md.OpenFiles[filename];
if (clientsList.Contains(clientName))
{
throw new FileIsOpenedException("File already open.");
}
md.OpenFiles[filename].Add(clientName);
}
else
{
if (!md.Files.ContainsKey(filename))
{
throw new FileNotFoundException("File does not exist.");
}
List<string> clientsList = new List<string>();
clientsList.Add(clientName);
md.OpenFiles.Add(filename, clientsList);
}
List<object> context = new List<object>();
string command = string.Format("OPEN {0} {1}", clientName, filename);
context.Add(md);
context.Add(command);
ThreadPool.QueueUserWorkItem(AppendToLog, context);
md.Log.Append(command);
return md.Files[filename];
}