Veritas File System
| Industry | Software |
|---|---|
| Founded | 1990 |
| Products | VERITAS File System (VxFS) |
The VERITAS File System (VxFS; referred to as JFS or OnlineJFS within HP-UX) is an extent-based file system created by VERITAS Software. Under an OEM partnership, VxFS functions as the default filesystem for the HP-UX platform. Marketed under the name OnlineJFS, it features licensed capabilities such as online defragmentation and resizing. Additionally, VxFS is compatible with several operating systems including AIX, Linux, Solaris, OpenSolaris, SINIX/Reliant UNIX, UnixWare, and SCO OpenServer. Initially designed for AT&T's Unix System Laboratories, VxFS is part of the Veritas Storage Foundation package alongside Veritas Volume Manager.
History
The vendor claims VxFS as the pioneering commercial journaling file system, either representing the earliest commercial implementation or the first standalone product in its category. According to developer Dan Koren, development commenced under contract with AT&T in 1990, with the initial release (version 1.0) occurring around 1991. Early adoption faced obstacles due to limited internet access at the time, which extended its commercialization period to approximately one to two years.
Version history
The on-disk structure of VxFS supports versioning and can be upgraded while mounted, with ten distinct versions released to date.
- Version 2 introduced features such as filesets, dynamic inode allocation, and ACLs; layouts 1 through 3 were deprecated starting with VxFS 4.0.
- Version 4 brought in storage checkpoints and compatibility with the Veritas Cluster File System; it debuted in VxFS 3.2.1 but was discontinued in VxFS 5.1.
- Version 5 expanded support to file systems up to 32 terabytes and individual files up to 2 TB; launched in VxFS 3.5 and removed in VxFS 5.1.
- Version 6 increased capacity limits to 8 exabytes, added named streams/resource forks, multi-volume support, and file change logging; introduced in VxFS 4.0.
- Version 7 improved multi-volume capabilities for Dynamic Storage Tiering, enabling policy-driven file placement and independent recovery of volumes; first seen in VxFS 5.0.
- Version 8 incorporated file-level snapshots and shared extents; introduced with VxFS 5.1.
- Version 9 added features like file compression, deduplication, and partition directories; debuted in VxFS 6.0.
- Version 10 implemented maxlink support, allowing directories to contain more than 64K subdirectories; introduced in VxFS 6.1.
Parallel access mode
VxFS can run either in a single instance mode or a parallel access/cluster mode. The parallel mode, branded as Veritas Cluster File System, permits multiple servers (cluster nodes) to concurrently access the same filesystem.
The Cluster File System guarantees cache consistency and compliance with POSIX standards across all nodes, ensuring atomic visibility of data modifications throughout the cluster. Sharing binary files and on-disk formats with single instance VxFS facilitates seamless switching between these modes.