AdvFS
| Industry | Computer hardware and software |
|---|---|
| Founded | November Expression error: Unrecognized word "dec"., 1957 |
| Headquarters | Bellevue, Washington , United States |
AdvFS, also referred to as the Tru64 UNIX Advanced File System, was created by Digital Equipment Corporation during the late 1980s through the mid-1990s specifically for their OSF/1 Unix platform, which later evolved into Digital UNIX and Tru64 UNIX. In June 2008, AdvFS was made available as open-source software under the GPL-2.0-only license. It has been widely adopted in environments that demand high availability and swift recovery following system interruptions.
Functionality
AdvFS introduces a sophisticated storage pool model known as a file domain, alongside logical file systems termed file sets. A file domain aggregates multiple block devices, including partitions, LVM, or LSM units. Within this domain, file sets operate as logical file systems. System administrators have the ability to dynamically add or remove volumes from an active file domain, provided that adequate storage capacity remains; data residing on disks slated for removal is seamlessly migrated online before detachment.
File sets facilitate load balancing by distributing file data across several physical volumes, and files may be striped over these volumes to enhance performance. Additionally, administrators can generate snapshots (referred to as clones) of both active and inactive file sets, enabling online backups and modifications without service interruption.
Moreover, block devices can be incorporated into or detached from a file domain while it continues functioning, allowing for hardware upgrades or replacements without necessitating downtime.
Features
Key attributes include:
- a journal that enables rapid recovery after crashes
- support for undeletion operations
- optimized performance capabilities
- a dynamic architecture permitting live file system adjustments
- snapshot creation during active use
- defragmentation processes that operate concurrently with users
On Linux platforms, AdvFS provides a ‘’syncv’’ system call designed to atomically apply changes across multiple files.
History
The development of AdvFS, also known as the Tru64 UNIX Advanced File System, was undertaken by engineers at Digital Equipment Corporation in Bellevue, Washington (DECwest) during the late 1980s. Its origins trace back to the discontinued OZIX operating system initiative.
Initially released with DEC OSF/1 (which later became Digital UNIX and then Tru64 UNIX), the development efforts alternated between Bellevue, WA and Nashua, NH. AdvFS versions were typically one increment behind their corresponding OS releases: for example, DEC OSF/1 version 3.2 included AdvFS version 2.x; Digital UNIX 4.0 shipped with AdvFS 3.x; and Tru64 UNIX 5.x featured AdvFS 4.x. Only AdvFS version 4 achieved production-grade stability accompanied by comprehensive administrative utilities. The development team had sufficient confidence in its log-based recovery mechanism to distribute it without an "fsck" tool, instead relying on mirrored drives for journal allocation.
In 1996, Lee and Thekkath documented the deployment of AdvFS atop the disk virtualization layer known as Petal. Subsequent studies contrasted their own distributed file system called Frangipani against AdvFS operating on Petal.
Research by Shapiro and Miller evaluated AdvFS's file storage performance relative to Oracle RDBMS 7.3.4 BLOB storage capabilities.
The Compaq Sierra Parallel File System (PFS) constructed a cluster file system by integrating multiple local AdvFS instances; testing conducted at Lawrence Livermore National Laboratory (LLNL) between 2000 and 2001 demonstrated satisfactory performance from AdvFS itself but revealed limitations in the clustering layer.
On June 23, 2008, Hewlett-Packard released the source code for AdvFS under the GPL-2.0-only license on SourceForge, ensuring its compatibility with the Linux kernel licensed under GPL-2.0-only.
External links
- Source code available on Sourceforge.net