【Redis】- 主從複製
Redis跟MySQL同樣，擁有很是強大的主從複製功能，並且還支持一個master能夠擁有多個slave，而一個slave又能夠擁有多個slave，從而造成強大的多級服務器集羣架構。
redis的主從複製是異步進行的，它不會影響master的運行，因此不會下降redis的處理性能。主從架構中，能夠考慮關閉Master的數據持久化功能，只讓Slave進行持久化，這樣能夠提升主服務器的處理性能。同時Slave爲只讀模式，這樣能夠避免Slave緩存的數據被誤修改。html
1.配置redis
實際生產中，主從架構是在幾個不一樣服務器上安裝相應的Redis服務。爲了測試方便，我這邊的主從備份的配置，都是在我Windows 本機上測試。緩存
1. 安裝兩個Redis 實例，Master和Slave。將Master端口設置爲6379，Slave 端口設置爲6380 。bind 都設置爲：127.0.0.1。 服務器
2. 在Slave 實例 ，增長：slaveof 127.0.0.1 6379 配置。以下圖所示:session
配置完成以後，啓動這兩個實例，若是輸出以下內容，說明主從複製的架構已經配置成功了。架構
注意：在同一臺電腦上測試，Master和Slave的端口不要同樣，不然是不能同時啓動兩個實例的。併發
2.測試app
在命令行，分別鏈接上Master服務器和Slave 服務器。而後在Master 寫入緩存，而後在Slave 中讀取。以下圖所示：異步
3.C#中調用性能
主從架構的Redis的讀寫其實和單臺Redis 的讀寫差很少，只是部分配置和讀取區分了主從，若是不清楚C#中如何使用redis，請參考我這篇文章 《Redis總結（二）C#中如何使用redis》。
須要注意的是：ServiceStack.Redis 中GetClient()方法，只能拿到Master redis中獲取鏈接，而拿不到slave 的readonly鏈接。這樣 slave起到了冗餘備份的做用，讀的功能沒有發揮出來，若是併發請求太多的話，則Redis的性能會有影響。
因此，咱們須要的寫入和讀取的時候作一個區分，寫入的時候，調用client.GetClient() 來獲取writeHosts的Master的redis 連接。讀取，則調用client.GetReadOnlyClient()來獲取的readonlyHost的 Slave的redis連接。
或者能夠直接使用client.GetCacheClient() 來獲取一個鏈接，他會在寫的時候調用GetClient獲取鏈接，讀的時候調用GetReadOnlyClient獲取鏈接，這樣能夠作到讀寫分離，從而利用redis的主從複製功能。
1. 配置文件 app.config
<!-- redis Start -->
<add key="SessionExpireMinutes" value="180" />
<add key="redis_server_master_session" value="127.0.0.1:6379" />
<add key="redis_server_slave_session" value="127.0.0.1:6380" />
<add key="redis_max_read_pool" value="300" />
<add key="redis_max_write_pool" value="100" />
<!--redis end-->
2. Redis操做的公用類RedisCacheHelper
using System; using System.Collections.Generic; using System.Configuration; using System.Linq; using System.Text; using System.Web; using ServiceStack.Common.Extensions; using ServiceStack.Redis; using ServiceStack.Logging; namespace Weiz.Redis.Common { public class RedisCacheHelper { private static readonly PooledRedisClientManager pool = null; private static readonly string[] writeHosts = null; private static readonly string[] readHosts = null; public static int RedisMaxReadPool = int.Parse(ConfigurationManager.AppSettings["redis_max_read_pool"]); public static int RedisMaxWritePool = int.Parse(ConfigurationManager.AppSettings["redis_max_write_pool"]); static RedisCacheHelper() { var redisMasterHost = ConfigurationManager.AppSettings["redis_server_master_session"]; var redisSlaveHost = ConfigurationManager.AppSettings["redis_server_slave_session"]; if (!string.IsNullOrEmpty(redisMasterHost)) { writeHosts = redisMasterHost.Split(','); readHosts = redisSlaveHost.Split(','); if (readHosts.Length > 0) { pool = new PooledRedisClientManager(writeHosts, readHosts, new RedisClientManagerConfig() { MaxWritePoolSize = RedisMaxWritePool, MaxReadPoolSize = RedisMaxReadPool, AutoStart = true }); } } } public static void Add<T>(string key, T value, DateTime expiry) { if (value == null) { return; } if (expiry <= DateTime.Now) { Remove(key); return; } try { if (pool != null) { using (var r = pool.GetClient()) { if (r != null) { r.SendTimeout = 1000; r.Set(key, value, expiry - DateTime.Now); } } } } catch (Exception ex) { string msg = string.Format("{0}:{1}發生異常!{2}", "cache", "存儲", key); } } public static void Add<T>(string key, T value, TimeSpan slidingExpiration) { if (value == null) { return; } if (slidingExpiration.TotalSeconds <= 0) { Remove(key); return; } try { if (pool != null) { using (var r = pool.GetClient()) { if (r != null) { r.SendTimeout = 1000; r.Set(key, value, slidingExpiration); } } } } catch (Exception ex) { string msg = string.Format("{0}:{1}發生異常!{2}", "cache", "存儲", key); } } public static T Get<T>(string key) { if (string.IsNullOrEmpty(key)) { return default(T); } T obj = default(T); try { if (pool != null) { using (var r = pool.GetClient()) { if (r != null) { r.SendTimeout = 1000; obj = r.Get<T>(key); } } } } catch (Exception ex) { string msg = string.Format("{0}:{1}發生異常!{2}", "cache", "獲取", key); } return obj; } public static void Remove(string key) { try { if (pool != null) { using (var r = pool.GetClient()) { if (r != null) { r.SendTimeout = 1000; r.Remove(key); } } } } catch (Exception ex) { string msg = string.Format("{0}:{1}發生異常!{2}", "cache", "刪除", key); } } public static bool Exists(string key) { try { if (pool != null) { using (var r = pool.GetClient()) { if (r != null) { r.SendTimeout = 1000; return r.ContainsKey(key); } } } } catch (Exception ex) { string msg = string.Format("{0}:{1}發生異常!{2}", "cache", "是否存在", key); } return false; } public static IDictionary<string, T> GetAll<T>(IEnumerable<string> keys) where T : class { if (keys == null) { return null; } keys = keys.Where(k => !string.IsNullOrWhiteSpace(k)); if (keys.Count() == 1) { T obj = Get<T>(keys.Single()); if (obj != null) { return new Dictionary<string, T>() { { keys.Single(), obj } }; } return null; } if (!keys.Any()) { return null; } IDictionary<string, T> dict = null; if (pool != null) { keys.Select(s => new { Index = Math.Abs(s.GetHashCode()) % readHosts.Length, KeyName = s }) .GroupBy(p => p.Index) .Select(g => { try { using (var r = pool.GetClient(g.Key)) { if (r != null) { r.SendTimeout = 1000; return r.GetAll<T>(g.Select(p => p.KeyName)); } } } catch (Exception ex) { string msg = string.Format("{0}:{1}發生異常!{2}", "cache", "獲取", keys.Aggregate((a, b) => a + "," + b)); } return null; }) .Where(x => x != null) .ForEach(d => { d.ForEach(x => { if (dict == null || !dict.Keys.Contains(x.Key)) { if (dict == null) { dict = new Dictionary<string, T>(); } dict.Add(x); } }); }); } IEnumerable<Tuple<string, T>> result = null; if (dict != null) { result = dict.Select(d => new Tuple<string, T>(d.Key, d.Value)); } else { result = keys.Select(key => new Tuple<string, T>(key, Get<T>(key))); } return result .Select(d => new Tuple<string[], T>(d.Item1.Split('_'), d.Item2)) .Where(d => d.Item1.Length >= 2) .ToDictionary(x => x.Item1[1], x => x.Item2); } } }
轉自：https://www.cnblogs.com/zhangweizhong/p/4980639.html