The document discusses REFLINK operations in OCFS2 which allow for space-efficient snapshots, clones, and copies of virtual machine images. It describes how OCFS2 implements reflinking by using reference counts for extents and copy-on-write when modifying reflinked files to avoid duplicating data. Examples show how reflinking images takes little time and space while allowing individual files to be modified without using more space. The status update notes that reflinking has been merged into recent Linux kernels and will be included in upcoming Oracle VM and OCFS2 releases.
4. REFLINK operations
int reflink(const char *oldpath,
const char *newpath, int preserve);
reflink()has the same calling semantics as cp(2)
but creates a new file that shares all the data extents of the source file
4
12. Status Update
REFLINK in OCFS2 has been merged into 2.6.32.
System call will be integrated into Linux Kernel soon.
OCFS2 1.6 for enterprise kernel will have REFLINK.
12
13. Status Update (Contd.)
Oracle VM 3.0 will have OCFS2 1.6.
OCFS2 will be one type of Oracle Storage Connect Program.
13