cache_dir
This directive instructs Squid where, and how, to store cached objects on disk. See Section 7.1 for the details on cache directories.
The second parameter selects the storage scheme. Your choices
are ufs, aufs, diskd, coss, and null. To use any scheme other than ufs, you must use the --enable-storeio option with ./configure. See Section 3.4.
The third parameter is the amount of disk space to use for the cache. The units are in megabytes.
The fourth and fifth parameters are the number of L1 and L2 directories. Don’t change these values for directories that already contain cached objects.
Some cache_dir schemes have additional, optional parameters. Refer to the scheme-specific sections in Chapter 8.