mongodb10---分片

<span style="color: #800000; font-weight: bold">1</span>:在3台独立服务器上,分别运行 <span style="color: #800000; font-weight: bold">27017</span>,<span style="color: #800000; font-weight: bold">27018</span>,27019实例, 互为副本集,形成3套repl <span style="color: #0000ff">set</span>
<span style="color: #800000; font-weight: bold">2</span><span style="color: #000000">: 在3台服务器上,各配置config server, 运行27020端口上
</span><span style="color: #800000; font-weight: bold">3</span><span style="color: #000000">: 配置mongos
.</span><span style="color: #808080">/</span>bin<span style="color: #808080">/</span>mongos <span style="color: #008080">--</span><span style="color: #008080">port 30000 \</span>
 <span style="color: #008080">--</span><span style="color: #008080">dbconfig 192.168.1.201:27020,192.168.1.202:27020,192.168.1.203:27020</span>
<span style="color: #800000; font-weight: bold">4</span><span style="color: #000000">:连接路由器
.</span><span style="color: #808080">/</span>bin<span style="color: #808080">/</span>mongo <span style="color: #008080">--</span><span style="color: #008080">port 30000</span>
<span style="color: #800000; font-weight: bold">5</span><span style="color: #000000">: 添加repl set为片
</span><span style="color: #808080">></span>sh.addShard(‘<span style="color: #800000; font-weight: bold">192.168</span>.<span style="color: #800000; font-weight: bold">1.201</span>:<span style="color: #800000; font-weight: bold">27017</span><span style="color: #000000">’);
</span><span style="color: #808080">></span>sh.addShard(‘<span style="color: #800000; font-weight: bold">192.168</span>.<span style="color: #800000; font-weight: bold">1.203</span>:<span style="color: #800000; font-weight: bold">27017</span><span style="color: #000000">’);
</span><span style="color: #808080">></span>sh.addShard(‘<span style="color: #800000; font-weight: bold">192.168</span>.<span style="color: #800000; font-weight: bold">1.203</span>:<span style="color: #800000; font-weight: bold">27017</span><span style="color: #000000">’);
</span><span style="color: #800000; font-weight: bold">6</span><span style="color: #000000">: 添加待分片的库
</span><span style="color: #808080">></span><span style="color: #000000">sh.enableSharding(databaseName);
</span><span style="color: #800000; font-weight: bold">7</span><span style="color: #000000">: 添加待分片的表
</span><span style="color: #808080">></span>sh.shardCollection(‘dbName.collectionName’,{field:<span style="color: #800000; font-weight: bold">1</span><span style="color: #000000">});
Field是collection的一个字段,系统将会利用filed的值,来计算应该分到哪一个片上.
这个filed叫”片键”, shard </span><span style="color: #0000ff">key</span>

<span style="color: #000000">mongodb不是从单篇文档的级别,绝对平均的散落在各个片上, 
而是N篇文档,形成一个块"chunk",
优先放在某个片上，片上又分为一个一个的块, 
当这片上的chunk,比另一个片的chunk,区别比较大时, (</span><span style="color: #808080">>=</span><span style="color: #800000; font-weight: bold">3</span><span style="color: #000000">) ,会把本片上的chunk,移到另一个片上, 以chunk为单位,
维护片之间的数据均衡
问: 为什么插入了10万条数据,才2个chunk?
答: 说明chunk比较大(默认是64M)
在config数据库中,修改chunksize的值.
</span><span style="color: #0000ff">Use</span><span style="color: #000000"> config
Show tables
Db.settings.find();    </span><span style="color: #808080">//</span>{id:’chunksize’,’value’:<span style="color: #800000; font-weight: bold">64</span><span style="color: #000000">}
问: 既然优先往某个片上插入,当chunk失衡时,再移动chunk,
自然,随着数据的增多,shard的实例之间,有chunk来回移动的现象,这将带来什么问题?
答: 服务器之间IO的增加, 
接上问: 能否我定义一个规则, 某N条数据形成1个块,预告分配M个chunk,
M个chunk预告分配在不同片上. 
以后的数据直接入各自预分配好的chunk,不再来回移动?
答: 能, 手动预先分片!</span>

mkdir <span style="color: #808080">-</span>p <span style="color: #808080">/</span>data<span style="color: #808080">/</span>r17 <span style="color: #808080">/</span>data<span style="color: #808080">/</span>r18 <span style="color: #808080">/</span>data<span style="color: #808080">/</span>r20 <span style="color: #808080">/</span>data<span style="color: #808080">/</span>mlog    <span style="color: #808080">//</span><span style="color: #800000; font-weight: bold">17</span><span style="color: #000000">,18是shard的端口，20是configsvr的端口
</span><span style="color: #808080">//</span><span style="color: #000000">启动2个mongo片的实例
</span><span style="color: #808080">/</span>usr<span style="color: #808080">/</span>local<span style="color: #808080">/</span>mongodb<span style="color: #808080">/</span>bin<span style="color: #808080">/</span>mongod <span style="color: #008080">--</span><span style="color: #008080">dbpath /data/r17/ --logpath /data/mlog/r17.log --port 27017 --fork --smallfile</span>
<span style="color: #808080">/</span>usr<span style="color: #808080">/</span>local<span style="color: #808080">/</span>mongodb<span style="color: #808080">/</span>bin<span style="color: #808080">/</span>mongod <span style="color: #008080">--</span><span style="color: #008080">dbpath /data/r18/ --logpath /data/mlog/r18.log --port 27018 --fork --smallfile</span>
<span style="color: #808080">//</span><span style="color: #000000">准备configsvc(不是一台存储数据的服务器，而是存储配置信息的服务器)
</span><span style="color: #808080">/</span>usr<span style="color: #808080">/</span>local<span style="color: #808080">/</span>mongodb<span style="color: #808080">/</span>bin<span style="color: #808080">/</span>mongod <span style="color: #008080">--</span><span style="color: #008080">dbpath /data/r20/ --logpath /data/mlog/r20.log --port 27020 --fork --configsvr</span>
<span style="color: #808080">//</span><span style="color: #000000">mongos路由器
</span><span style="color: #808080">/</span>usr<span style="color: #808080">/</span>local<span style="color: #808080">/</span>mongodb<span style="color: #808080">/</span>bin<span style="color: #808080">/</span>mongos <span style="color: #008080">--</span><span style="color: #008080">logpath /data/mlog/r30.log --port 30000 --configdb 192.168.202:27020   --fork//哪台configsvr为他服务，现在mongos和configsvr连在了一起但是还没有和shard连在一起。</span>
<span style="color: #000000">
ps aux </span><span style="color: #808080">|</span> grep mongo    <span style="color: #808080">//</span><span style="color: #000000">可以看到刚才的4个进程
</span><span style="color: #808080">//</span><span style="color: #000000">连接mongos
.</span><span style="color: #808080">/</span>bin<span style="color: #808080">/</span>mongo <span style="color: #008080">--</span><span style="color: #008080">port 30000</span>
<span style="color: #808080">//</span><span style="color: #000000">添加repl set为片,现在3者都连接到一起了，
</span><span style="color: #808080">></span>sh.addShard(‘<span style="color: #800000; font-weight: bold">192.168</span>.<span style="color: #800000; font-weight: bold">1.201</span>:<span style="color: #800000; font-weight: bold">27017</span><span style="color: #000000">’);
</span><span style="color: #808080">></span>sh.addShard(‘<span style="color: #800000; font-weight: bold">192.168</span>.<span style="color: #800000; font-weight: bold">1.203</span>:<span style="color: #800000; font-weight: bold">27018</span><span style="color: #000000">’);   
sh.status()   </span><span style="color: #808080">//</span><span style="color: #000000">可以查看分片信息
</span><span style="color: #0000ff">use</span><span style="color: #000000"> test
db.stu.</span><span style="color: #0000ff">insert</span><span style="color: #000000">({ss:"ss"})
db.stu.</span><span style="color: #0000ff">insert</span><span style="color: #000000">({ss:"ss"})
db.stu.</span><span style="color: #0000ff">insert</span><span style="color: #000000">({ss:"ss"})
db.stu.</span><span style="color: #0000ff">insert</span><span style="color: #000000">({ss:"ss"})
db.stu.</span><span style="color: #0000ff">insert</span><span style="color: #000000">({ss:"ss"})
</span><span style="color: #808080">//</span><span style="color: #000000">连接到27017
.</span><span style="color: #808080">/</span>bin<span style="color: #808080">/</span>mongo <span style="color: #008080">--</span><span style="color: #008080">port 27017</span>
db.find()    <span style="color: #808080">//</span><span style="color: #000000">有数据
</span><span style="color: #808080">//</span><span style="color: #000000">连接到27018
.</span><span style="color: #808080">/</span>bin<span style="color: #808080">/</span>mongo <span style="color: #008080">--</span><span style="color: #008080">port 27018</span>
db.find()    <span style="color: #808080">//</span><span style="color: #000000">没有数据，因为没有指定分片规则
</span><span style="color: #808080">//</span><span style="color: #000000">添加待分片的库(谁可以分片)
</span><span style="color: #808080">></span>sh.enableSharding(<span style="color: #ff0000">‘</span><span style="color: #ff0000">shop</span><span style="color: #ff0000">‘</span>);      <span style="color: #808080">//</span><span style="color: #000000">shop库可以分片
sh.status()    </span><span style="color: #808080">//</span><span style="color: #000000">可以看到shop库可以分片
</span><span style="color: #808080">//</span><span style="color: #000000">添加待分片的表
</span><span style="color: #808080">></span>sh.shardCollection(<span style="color: #ff0000">‘</span><span style="color: #ff0000">shop.goods</span><span style="color: #ff0000">‘</span>,{goods_id:<span style="color: #800000; font-weight: bold">1</span><span style="color: #000000">});
sh.status()    </span><span style="color: #808080">//</span><span style="color: #000000">可以看到shop库goods表的状态
</span><span style="color: #808080">//</span><span style="color: #000000">添加2000数据
</span><span style="color: #0000ff">use</span><span style="color: #000000"> shop
</span><span style="color: #0000ff">for</span>(<span style="color: #ff00ff">var</span> i<span style="color: #808080">=</span><span style="color: #800000; font-weight: bold">1</span>;i<span style="color: #808080"><</span><span style="color: #800000; font-weight: bold">600000</span>;i<span style="color: #808080">++</span><span style="color: #000000">){
    db.goods.</span><span style="color: #0000ff">insert</span>({ss:"ss"<span style="color: #808080">+</span><span style="color: #800000; font-weight: bold">1</span><span style="color: #000000">})
}
db.goods.find()
</span><span style="color: #808080">//</span><span style="color: #000000">查看分片数据
.</span><span style="color: #808080">/</span>bin<span style="color: #808080">/</span>mongo <span style="color: #008080">--</span><span style="color: #008080">port 27017</span>
<span style="color: #000000">db.find()
.</span><span style="color: #808080">/</span>bin<span style="color: #808080">/</span>mongo <span style="color: #008080">--</span><span style="color: #008080">port 27018</span>
db.find()

mongodb10---分片

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