Cowloop
The cowloop-driver is a copy-on-write loop driver (block device) which can be used on top of any other block driver. It shields the lower driver from any write access. Instead, it diverts all write-accesses to an arbitrary regular file, called the cowfile. When a modified block is read again later on, the cowloop-driver obtains the block from the cowfile, while non-modified blocks are obtained from the original read-only device. This mechanism allows block-devices to be used in a read-write fashion without modifying the underlying block-device itself.
| Licenses | GPL |
|---|---|
| Operating Systems | POSIX Linux |
| Implementation | C |
Recent releases
- 12 Dec 2006 22:54
Release Notes: The driver went through an extensive redesign and upgrade. Several new management utilities were added, based on new driver IOCTLs. An important bugfix cures the (sometimes occurring) 'Scheduling while atomic' problem. Greatly improved manual pages were added.
- 13 Jun 2005 08:30
Release Notes: A 'cowmerge' command that merges all modifications stored in a cowfile into the base file (rdofile) was added. It is possible now to open the same cowdevice more than once to allow filesystems like reiserfs and xfs to be used on a cowdevice.
- 09 Mar 2005 12:19
Release Notes: Support for 254 cowdevices to be used in parallel, where every cowdevice consists of a read-only file and related cowfile. Support for read-only files and cowfiles larger than 2 Gbytes was added.
- 15 Dec 2004 14:13
No changes have been submitted for this release.
atconsultancy
15 Nov 2004 07:13
