Why HBase disable a large table taking very long time

Jean-Daniel Cryans 在apache mail list: http://comments.gmane.org/gmane.comp.java.hadoop.hbase.user/15699
上给了一个答复，另外HBase貌似在考虑使用async的方式，也就是说用户发出了disable以后马上返回，但是用户可以调用一个阻塞的命令来查看disable是否完成，有兴趣的读者可以关注一下！

To disable a region, it's memstore must first be flushed. That's done
sequentially for all regions that must be disabled inside a table.
There's not really a way around it unless you don't need that data.
If you're planning to disable a table but at the same time need it to
be unavailable for the shortest time possible, I recommend calling a
flush on the table from the shell first and then some time later doing
the disable. How much later you ask? Well there's currently no easy
way to tell, I usually just tail any region server log file until I
see they're done.