On Mon October 27 2008, Ed W wrote: > > >> What is the argument against unifying everything? > >> > > > > on recente kernels (i.e. in the presence of > > CoW Link Breaking), the only case where a > > unified file might not work is when some > > application checks the file properties and > > requires them to have a link count of 1 > > > > > Subtle extra one, but as I understand it, the COW stuff breaks ALL > hardlinks on write, so if you have a bunch of hard links within the > vserver for some internal process, then additionally hardlinking those > *across* vservers will cause all the hardlinks (even within the vserver) > to be broken if the file is ever altered. This may or may not be a > problem in general (seems like a corner case for most people?) > It does not work that way here (2.6.27.4+vs2.3) I am using CoW to detect changes to files in replicated development trees - Given a file (inode) with 8 (upto 4000+ in my experience) different appearances in the directory tree - Changing it creates one, total of (2) inodes, one with a link count of 7 and the changed one with a link count of 1. > Herbert - when I quickly looked at the code for the unification utility, > it *appeared* to be figuring out whether a file already is hardlinked. > Would it be as straightforward as it might appear to add a test to avoid > hardlinking files across vservers if they are already hardlinked > *within* a vserver? > > Gentoo uses hardlinks within an installation for various (good) > reasons. Would like to preserve these where possible > Do not set +iunlink +immutable on those. CoW will ignore them. Mike > Cheers > > Ed W >