| Global File System | |
| ------------------ | |
| https://fedorahosted.org/cluster/wiki/HomePage | |
| GFS is a cluster file system. It allows a cluster of computers to | |
| simultaneously use a block device that is shared between them (with FC, | |
| iSCSI, NBD, etc). GFS reads and writes to the block device like a local | |
| file system, but also uses a lock module to allow the computers coordinate | |
| their I/O so file system consistency is maintained. One of the nifty | |
| features of GFS is perfect consistency -- changes made to the file system | |
| on one machine show up immediately on all other machines in the cluster. | |
| GFS uses interchangeable inter-node locking mechanisms, the currently | |
| supported mechanisms are: | |
| lock_nolock -- allows gfs to be used as a local file system | |
| lock_dlm -- uses a distributed lock manager (dlm) for inter-node locking | |
| The dlm is found at linux/fs/dlm/ | |
| Lock_dlm depends on user space cluster management systems found | |
| at the URL above. | |
| To use gfs as a local file system, no external clustering systems are | |
| needed, simply: | |
| $ mkfs -t gfs2 -p lock_nolock -j 1 /dev/block_device | |
| $ mount -t gfs2 /dev/block_device /dir | |
| If you are using Fedora, you need to install the gfs2-utils package | |
| and, for lock_dlm, you will also need to install the cman package | |
| and write a cluster.conf as per the documentation. For F17 and above | |
| cman has been replaced by the dlm package. | |
| GFS2 is not on-disk compatible with previous versions of GFS, but it | |
| is pretty close. | |
| The following man pages can be found at the URL above: | |
| fsck.gfs2 to repair a filesystem | |
| gfs2_grow to expand a filesystem online | |
| gfs2_jadd to add journals to a filesystem online | |
| tunegfs2 to manipulate, examine and tune a filesystem | |
| gfs2_convert to convert a gfs filesystem to gfs2 in-place | |
| mkfs.gfs2 to make a filesystem |