layoutemulator.h

nandflash文件系统源代码

//---------------------------------------------------------- -*- Mode: C++ -*-
// $Id: LayoutEmulator.h $
//
// Created 2008/08/08
//
// Author: Sriram Rao
//
// Copyright 2008 Quantcast Corp.
//
// This file is part of Kosmos File System (KFS).
//
// Licensed under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with
// the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
// implied. See the License for the specific language governing
// permissions and limitations under the License.
//
// \brief Emulator for the layout manager: read in a chunk->location
// map; we can then migrate blocks around to experiment with placement algorithms.
//
//----------------------------------------------------------------------------

#ifndef EMULATOR_LAYOUTEMULATOR_H
#define EMULATOR_LAYOUTEMULATOR_H

#include <string>
#include <map>
#include <tr1/unordered_map>
#include "meta/LayoutManager.h"

namespace KFS
{

    class LayoutEmulator : public LayoutManager {
    public:
        LayoutEmulator() {
            SetMinChunkserversToExitRecovery(0);
            ToggleRebalancing(true);
        };

        // Given a chunk->location data in a file, rebuild the chunk->location map.
        //
        int LoadChunkmap(const std::string &chunkLocationFn, bool addChunksToReplicationChecker = false);

        void AddServer(const ServerLocation &loc, int rack, float totalSpaceGB);

        void SetupForRebalancePlanning() {
            mDoingRebalancePlanning = true;
        }
        int SetRebalancePlanOutFile(const std::string &rebalancePlanFn);
        int BuildRebalancePlan();

        void ExecuteRebalancePlan();

        void PrintChunkserverBlockCount();

        void ReadNetworkDefn(const std::string &networkFn);

        int VerifyRackAwareReplication(bool checkSize, bool verbose);

        seq_t GetChunkversion(fid_t fid, chunkId_t cid);

        size_t GetChunkSize(chunkId_t cid);

        vector<size_t> GetChunkSizes(chunkId_t cid);

        void MarkServerDown(const ServerLocation &loc);
    private:
        void Parse(const char *line, bool addChunksToReplicationChecker);
        bool mDoingRebalancePlanning;
        std::tr1::unordered_map<chunkId_t, std::vector<size_t> > mChunkSize;
    };

    extern LayoutEmulator gLayoutEmulator;
}

#endif // EMULATOR_LAYOUTEMULATOR_H