portsnap

FreeBSD 5.5和6.1开始内建了 portsnap，portsnap是一种新的 ports 套件同步机制。

与传统的 cvsup 更新方式相比， portsnap 有一些优越性：

• 对于经常进行更新的情况，portsnap很快：portsnap包含索引和具体的ports两部分，在更新的时候它首先会更新索引，而具体的更新则是下载两次索引描述的文件之间的差异，因此可以大大节省带宽。
• portsnap有数字签名：cvsup并不包含任何加密或数字签名的机制，而portsnap的公钥则是通过光盘发给每一台机器的，相对来说安全性要好的多。
• portsnap使用HTTP协议：通常，企业防火墙并不会拦截HTTP。

早先，架设portsnap镜像的方法比较复杂。由于portsnap的设计，架设portsnap镜像所产生的流量，在通常情况下大约会是仅做portsnap操作的3000倍左右。

Xorg 7.2 imported，然后今天……

[delphij@tarsier] ~> sudo portsnap fetch update
Looking up portsnap.FreeBSD.org mirrors… 3 mirrors found.
Fetching snapshot tag from portsnap1.FreeBSD.org… done.
Fetching snapshot metadata… done.
Updating from Fri May 18 03:22:40 CST 2007 to Sun May 20 20:53:40 CST 2007.
Fetching 3 metadata patches.. done.
Applying metadata patches… done.
Fetching 0 metadata files… done.

Colin has finally added portsnap and related stuff (bsdiff, etc) to FreeBSD 7.0-CURRENT. This would not be MFC’ed before 6.0-RELEASE, but still good enough because it will attract more users to use it.

Portsnap is a secure and efficient alternative to the current ports tree update approach. Since it goes through HTTP, it is much easier than other existing methods to use it to obtain ports, especially from some brain-damaged administrated networks.

This is an important step of getting the tools like freebsd-update and portsnap into base system, which provides good method of updating the base system (through binary updates) and ports tree.