之前做了一个Redis的集群方案，跑了小半年，线上运行的很稳定
差不多可以跟大家分享下经验，前面写了一篇文章 数据在线服务的一些探索经验，可以做为背景阅读

应用

集群状况

集群方案

整体设计

RedisKey

public class RedisKey implements Serializable{
	private static final long serialVersionUID = 1L;
	
	//每个业务不同的family
	private String family;
	
	private String key;
		
	......	
	//物理保存在Redis上的key为经过MurmurHash之后的值
	private String makeRedisHashKey(){
		return String.valueOf(MurmurHash.hash64(makeRedisKeyString()));
	}
	
	//ReidsKey由family.key组成
	private String makeRedisKeyString(){
		return family +":"+ key;
	}

	//返回用户的经过Hash之后RedisKey
	public String getRedisKey(){
		return makeRedisHashKey();
	}
	.....
}

Family的存在时为了避免多个业务key冲突，给每个业务定义自己独立的Faimily
出于性能考虑，参考Redis存储设计，实际保存在Redis上的key为经过hash之后的值

接口

public interface RedisUseInterface{
	/**
	 * 通过RedisKey获取value
	 * 
	 * @param redisKey
	 *           redis中的key
	 * @return 
	 *           成功返回value,查询不到返回NULL
	 */
	public String get(final RedisKey redisKey) throws Exception;
	
	/**
	 * 插入<k,v>数据到Redis
	 * 
	 * @param redisKey
	 *           the redis key
	 * @param value
	 *           the redis value
	 * @return 
	 *           成功返回"OK",插入失败返回NULL
	 */
	public String set(final RedisKey redisKey, final String value) throws Exception;
	
	/**
	 * 批量写入数据到Redis
	 * 
	 * @param redisKeys
	 *           the redis key list
	 * @param values
	 *           the redis value list
	 * @return 
	 *           成功返回"OK",插入失败返回NULL
	 */
	public String mset(final ArrayList<RedisKey> redisKeys, final ArrayList<String> values) throws Exception;
	
	
	/**
	 * 从Redis中删除一条数据
	 * 
	 * @param redisKey
	 *           the redis key
	 * @return 
	 *           an integer greater than 0 if one or more keys were removed 0 if none of the specified key existed
	 */
	public Long del(RedisKey redisKey) throws Exception;
	
	/**
	 * 从Redis中批量删除数据
	 * 
	 * @param redisKey
	 *           the redis key
	 * @return 
	 *           返回成功删除的数据条数
	 */
	public Long del(ArrayList<RedisKey> redisKeys) throws Exception;
	
	/**
	 * 插入<k,v>数据到Redis
	 * 
	 * @param redisKey
	 *           the redis key
	 * @param value
	 *           the redis value
	 * @return 
	 *           成功返回"OK",插入失败返回NULL
	 */
	public String setByte(final RedisKey redisKey, final byte[] value) throws Exception;
	
	/**
	 * 插入<k,v>数据到Redis
	 * 
	 * @param redisKey
	 *           the redis key
	 * @param value
	 *           the redis value
	 * @return 
	 *           成功返回"OK",插入失败返回NULL
	 */
	public String setByte(final String redisKey, final byte[] value) throws Exception;
	
	/**
	 * 通过RedisKey获取value
	 * 
	 * @param redisKey
	 *           redis中的key
	 * @return 
	 *           成功返回value,查询不到返回NULL
	 */
	public byte[] getByte(final RedisKey redisKey) throws Exception;
	
	/**
	 * 在指定key上设置超时时间
	 * 
	 * @param redisKey
	 *           the redis key
	 * @param seconds
	 * 			 the expire seconds
	 * @return 
	 *           1:success, 0:failed
	 */
	public Long expire(RedisKey redisKey, int seconds) throws Exception;
}

写Redis流程

		//获取写哪个Redis Node
		int slot = getSlot(keyHash);
		RedisDataNode redisNode =  rdList.get(slot);

		//写Master
		JedisSentinelPool jp = redisNode.getSentinelPool();
		Jedis je = null;
		boolean success = true;
		try {
			je = jp.getResource();
			return je.set(key, value);
		} catch (Exception e) {
			log.error("Maybe master is down", e);
			e.printStackTrace();
			success = false;
			if (je != null)
				jp.returnBrokenResource(je);
			throw e;
		} finally {
			if (success && je != null) {
				jp.returnResource(je);
			}
		}

读流程

		//获取读哪个Redis Node
		int slot = getSlot(keyHash);
		RedisDataNode redisNode =  rdList.get(slot);

		//根据权重选取一个工作Instatnce
		int rn = redisNode.getWorkInstance();

		//轮询
		int cursor = rn;
		do {			
			try {
				JedisPool jp = redisNode.getInstance(cursor).getJp();
				return getImpl(jp, key);
			} catch (Exception e) {
				log.error("Maybe a redis instance is down, slot : [" + slot + "]" + e);
				e.printStackTrace();
				cursor = (cursor + 1) % redisNode.getInstanceCount();
				if(cursor == rn){
					throw e;
				}
			}
		} while (cursor != rn);

权重计算

	public int getWorkInstance() {
		//没有定义weight，则完全随机选取一个redis instance
		if(maxWeight == 0){
			return (int) (Math.random() * RANDOM_SIZE % redisInstanceList.size());
		}
		
		//获取随机数
		int rand = (int) (Math.random() * RANDOM_SIZE % maxWeight);
		int sum = 0;
	
		//选取Redis Instance
		for (int i = 0; i < redisInstanceList.size(); i++) {
			sum += redisInstanceList.get(i).getWeight();
			if (rand < sum) {
				return i;
			}
		}
		
		return 0;
	}

Redis集群方案及实现