HP Open Sources the Tru64 AdvFS File System

HP decided to help the Linux file system innovation by open sourcing its Tru64 Advanced File System, or AdvFS. This file system comes from Digital Unix (created by Digital Equipment Corporation) and is used by HP customers in mission-critical deployments. After several acquisitions, HP created HP-UX, a flavor of Unix, with its own file system. Tru64 AdvFS was offered to DEC (acquired by Compaq ten years ago), Compaq and HP customers. Compaq and HP became one single company in 2002.

HP decided to use the second version of the GPL license for its file system, so it can be compatible with the license used by the Linux kernel (which also uses GPLv2). A developer can take all the parts they want from AdvFS and use them in different applications.

Martin Fink, senior vice president and general manager, Business Critical Systems at HP, said: "To ensure the highest levels of data security and availability, Linux customers need full and immediate access to established technology. We continue to invest our engineering resources in the development of that technology, while working with the open source community to ensure accessibility and seamless integration."

AdvFS is a high performance journaling file system that allows fast recovery after a system crash. Thanks to its dynamic structure, one can manage the file system on the fly and once more, on the fly, system snapshots can be created.

AdvFS's storage pool is called "file domain" (made up of block devices) and its logical file systems are called "file sets". The latter can be balanced, which means that the content on these sets can be balanced across physical volumes. The snapshots, or clones, allow a system administrator to easily create on-line backups; an interesting feature of AdvFS is the one that allows a sysadmin to add or remove block devices from a file domain even if the latter has active users. This feature is really good when it comes to migrating to larger devices or from faulty hardware without shutting down the system.

This file system supports volumes that have a maximum size of 16 TB and the names of the files must not have more than 255 bytes in length.