HBase 默认刷写文件 flush_compact.xml 注释解析

flush_compact.xml

    <!-- 一个store里面允许存的hfile的个数，超过这个个数会被写到新的一个hfile里面 也即是每个region的每个列族对应的memstore在fulsh为hfile的时候，默认情况下当超过3个hfile的时候就会   
        对这些文件进行合并重写为一个新文件，设置个数越大可以减少触发合并的时间，但是每次合并的时间就会越长 -->  
    <property>  
        <name>hbase.hstore.compactionThreshold</name>  
        <value>3</value>  
        <description>  
            If more than this number of HStoreFiles in any one HStore  
            (one HStoreFile is written per flush of memstore) then a compaction  
            is run to rewrite all HStoreFiles files as one. Larger numbers  
            put off compaction but when it runs, it takes longer to complete.  
        </description>  
    </property>  
    <!-- 每个minor compaction操作的 允许的最大hfile文件上限 -->  
    <property>  
        <name>hbase.hstore.compaction.max</name>  
        <value>10</value>  
        <description>Max number of HStoreFiles to compact per 'minor'  
            compaction.</description>  
    </property>  


    <!-- regionServer的全局memstore的大小，超过该大小会触发flush到磁盘的操作,默认是堆大小的40%,而且regionserver级别的   
        flush会阻塞客户端读写 -->  
    <property>  
        <name>hbase.regionserver.global.memstore.size</name>  
        <value></value>  
        <description>Maximum size of all memstores in a region server before  
            new  
            updates are blocked and flushes are forced. Defaults to 40% of heap (0.4).  
            Updates are blocked and flushes are forced until size of all  
            memstores  
            in a region server hits  
            hbase.regionserver.global.memstore.size.lower.limit.  
            The default value in this configuration has been intentionally left  
            emtpy in order to  
            honor the old hbase.regionserver.global.memstore.upperLimit property if  
            present.  
        </description>  
    </property>  
        <!-- 内存中的文件在自动刷新之前能够存活的最长时间，默认是1h -->  
    <property>  
        <name>hbase.regionserver.optionalcacheflushinterval</name>  
        <value>3600000</value>  
        <description>  
            Maximum amount of time an edit lives in memory before being automatically  
            flushed.  
            Default 1 hour. Set it to 0 to disable automatic flushing.  
        </description>  
    </property>  
     <!-- 单个region里memstore的缓存大小，超过那么整个HRegion就会flush,默认128M -->  
    <property>  
        <name>hbase.hregion.memstore.flush.size</name>  
        <value>134217728</value>  
        <description>  
            Memstore will be flushed to disk if size of the memstore  
            exceeds this number of bytes. Value is checked by a thread that runs  
            every hbase.server.thread.wakefrequency.  
        </description>  
    </property>