 | The article's lead section may need to be rewritten. (July 2012) |
| Developer(s) | IBM et al. |
|---|---|
| Full name | IBM Journaled File System |
| Introduced | 1990 and 1999 with JFS1 in AIX 3.1 and JFS in OS/2 4.5 |
| Partition IDs | 0x35 (MBR) |
| Structures | |
| Directory contents | B+ tree |
| File allocation | Bitmap/extents |
| Limits | |
| Max volume size | 32 × 250 bytes (32 PiB) |
| Max file size | 4 × 250 bytes (4 PiB) |
| Max no. of files | No limit defined |
| Max filename length | 255 bytes |
| Allowed filename characters | Any Unicode except NUL |
| Features | |
| Dates recorded | Modification (mtime), attribute modification (ctime), access (atime) |
| Date resolution | 1 ns |
| Forks | Yes |
| File system permissions | Unix permissions, ACLs |
| Transparent compression | Only in JFS1 on AIX |
| Transparent encryption | No (provided at the block device level) |
| Data deduplication | No |
| Other | |
| Supported operating systems | AIX, OS/2, Linux, eComStation, ArcaOS |
Journaled File System (JFS) is a 64-bit journaling file system created by IBM. There are versions for AIX, OS/2, eComStation, ArcaOS and Linux operating systems. The latter is available as free software under the terms of the GNU General Public License (GPL). HP-UX has another, different filesystem named JFS that is actually an OEM version of Veritas Software's VxFS.
In the AIX operating system, two generations of JFS exist, which are called JFS (JFS1) and JFS2 respectively.[1]
IBM's JFS was originally designed for 32-bit systems. JFS2 was designed for 64-bit systems.[2]
In other operating systems, such as OS/2 and Linux, only the second generation exists and is called simply JFS.[3] This should not be confused with JFS in AIX that actually refers to JFS1.
- ^ "A Mini-FAQ for JFS". JFS for Linux project.
- ^ "IBM JFS and JFS2". IBM.
- ^ "Interview with the People Behind JFS, ReiserFS & XFS".