On Tue, 2007-07-24 at 18:57 -0500, Douglas McClendon wrote: > Jeremy Katz wrote: > > On Mon, 2007-07-23 at 03:06 -0500, Douglas McClendon wrote: > >> They implement what I have described rather verbosely on > >> fedora-livecd-list and > >> in bug 248082. > >> > >> The short story is the fedora7 livecd installer works by copying a 4G ext3 > >> image > >> to the destination rootfs, and then resizing to maximal size. > >> > >> The attached patches improve the speed of this step by 10-30% (for cdrom > >> vs fast > >> livecd-iso-to-disk'd usbflash install media respectively). > >> > >> This is accomplished because the 4G image actually only holds 2G of data. > >> The > >> patch to livecd-creator, when invoked with --turbo-liveinst, will create a > >> small > >> (25kb) binary delta file on the livecd. The patch to anaconda, will > >> detect the > >> presence of the file, and if it is there, use it with devicemapper to > >> create a > >> 2G ext3 image, which can naturally be copied to the destination volume > >> more > >> quickly. (I.e. 2G of zeros don't get written to disk). > > > > So I'm still not convinced that the wins here are really substantial > > enough given the additional contortions that we have to go through to > > get things going. > > I understand your attitude. I will however do another round of polishing and > performance testing in an attempt to convince you. Ultimately, I hope to at > least convince you to do your own side-by-side taste test and confirm my > results. :)
*grin* Sounds good. > > As for being able to get to a smaller rootfs, I think that if you really > > want to get to requiring a small root, then we have to entirely change > > the copying to be more of a "copy the bits from the filesystem" as > > opposed to a block-level copy. That would also avoid the duplicated > > copies if you have, eg, a separate /usr (and also avoid the overhead of > > needing that space on the rootfs). This would also end up avoiding the > > copying overhead as well as the filesystem resizing, although you'd then > > have to format the entire fs. I think I'd be slightly more interested > > in doing that, although care has to be taken to ensure that we really > > are preserving everything then. > > I agree with all of this. Still, I go back to the existing patch, which > hopefully should be a bit more elegant and polished soon, and suggest that it > is > at least worth seriously considering for F8. Doing a file level copy rather than the block copy currently being done, though, should be pretty straight-forward also. It'd just be changing the copy method in the livecd backend of anaconda to use the copytree stuff that's already there. Maybe I'll try to throw together a quick test to time later and see how it fares. I know it'll be a win for if you have a separate /usr, the question is just for the "base" case. Jeremy -- Fedora-livecd-list mailing list [email protected] https://www.redhat.com/mailman/listinfo/fedora-livecd-list
