Less known Solaris Features: CacheFS - Part 1: Introduction

There is a hidden gem in the Solaris Operating Environment called CacheFS, solving a task many admins solve with scripts. Imagine the following situation. You have a central fileserver, and let´s say a 40 webservers. All this webservers deliver static content, this content is stored on the harddisk of the fileserver. Later you recognize, that your fileserver is really loaded by the webservers. Harddisks are cheap, thus most admins will start to use an recursive rcp or an rsync to put a copy of the data to the webserver disks. Well … Solaris gives you a tool to solve this problem without scripting, without cron based jobs, just by using NFSv3 and this hidden gem: CacheFS. CacheFS is a really nifty tool. It does exactly what the name says. It´s an filesystem, that caches data of an other filesystem. You have to think about it like a layered cake. You mount a CacheFS filesystem with an parameter that tells CacheFS to mount another one in the background.