aosp mirror

These instructions assume that the mirror is created in /usr/local/aosp/mirror. The first step is to create and sync the mirror itself, which uses close to 13GB of network bandwidth and a similar amount of disk space. Notice the --mirror flag, which can only be specified when creating a new client:

$ mkdir -p /usr/local/aosp/mirror
$ cd /usr/local/aosp/mirror
$ repo init -u https://android.googlesource.com/mirror/manifest --mirror
$ repo sync

Once the mirror is synced, new clients can be created from it. Note that it's important to specify an absolute path:

$ mkdir -p /usr/local/aosp/kitkat
$ cd /usr/local/aosp/kitkat
$ repo init -u /usr/local/aosp/mirror/platform/manifest.git -b android-4.4.4
$ repo sync

Finally, to sync a client against the server, the mirror needs to be synced against the server, then the client against the mirror:

$ cd /usr/local/aosp/mirror
$ repo sync
$ cd /usr/local/aosp/kitkat
$ repo sync

ref:  http://stackoverflow.com/questions/15870217/android-source-code-and-repo-what-exactly-is-happening-when-getting-code