squid cache_dir

Usage:

	cache_dir Type Directory-Name Fs-specific-data [options]

实例:
cache_dir aufs /raid/squid0 50000 16 256
cache_dir aufs /raid/squid1 50000 16 256
	
Type: 存储类型包括ufs,aufs,diskd,coss,null,现在3.1版本中null已经没有了. 存储类型可以指定多个,但是
必须使用不同的分区.

The aufs store type:

	"aufs" uses the same storage format as "ufs", utilizing
	POSIX-threads to avoid blocking the main Squid process on
	disk-I/O. This was formerly known in Squid as async-io.

	cache_dir aufs Directory-Name Mbytes L1 L2 [options]