GFS2
| Developer(s) | Red Hat |
|---|---|
| Full name | Global File System 2 |
| Introduced | 2005 with Linux 2.6.19 |
| Structures | |
| Directory contents | Hashed (small directories stuffed into inode) |
| File allocation | bitmap (resource groups) |
| Bad blocks | No |
| Limits | |
| Max no. of files | Variable |
| Max filename length | 255 bytes |
| Allowed filename characters | All except NUL |
| Features | |
| Dates recorded | attribute modification (ctime), modification (mtime), access (atime) |
| Date resolution | Nanosecond |
| Attributes | No-atime, journaled data (regular files only), inherit journaled data (directories only), synchronous-write, append-only, immutable, exhash (dirs only, read only) |
| File system permissions | Unix permissions, ACLs and arbitrary security attributes |
| Transparent compression | No |
| Transparent encryption | No |
| Data deduplication | across nodes only |
| Other | |
| Supported operating systems | Linux |
| Developer(s) | Red Hat (formerly, Sistina Software) |
|---|---|
| Full name | Global File System |
| Introduced | 1996 with IRIX (1996), Linux (1997) |
| Structures | |
| Directory contents | Hashed (small directories stuffed into inode) |
| File allocation | bitmap (resource groups) |
| Bad blocks | No |
| Limits | |
| Max no. of files | Variable |
| Max filename length | 255 bytes |
| Allowed filename characters | All except NUL |
| Features | |
| Dates recorded | attribute modification (ctime), modification (mtime), access (atime) |
| Date resolution | 1s |
| Attributes | No-atime, journaled data (regular files only), inherit journaled data (directories only), synchronous-write, append-only, immutable, exhash (dirs only, read only) |
| File system permissions | Unix permissions, ACLs |
| Transparent compression | No |
| Transparent encryption | No |
| Data deduplication | across nodes only |
| Other | |
| Supported operating systems | IRIX (now obsolete), FreeBSD (now obsolete), Linux |
In computing, the Global File System 2 (GFS2) is a shared-disk file system for Linux computer clusters. GFS2 allows all members of a cluster to have direct concurrent access to the same shared block storage, in contrast to distributed file systems which distribute data throughout the cluster. GFS2 can also be used as a local file system on a single computer.
GFS2 has no disconnected operating-mode, and no client or server roles. All nodes in a GFS2 cluster function as peers. Using GFS2 in a cluster requires hardware to allow access to the shared storage, and a lock manager to control access to the storage. The lock manager operates as a separate module: thus GFS2 can use the distributed lock manager (DLM) for cluster configurations and the "nolock" lock manager for local filesystems. Older versions of GFS also support GULM, a server-based lock manager which implements redundancy via failover.
GFS and GFS2 are free software, distributed under the terms of the GNU General Public License.