[Cc-ing debian-live mailinglist, not sure whether they are interested in LZMA but if so they should be aware of it.] * Jonathan Nieder <jrnieder@gmail.com> [20091103 00:14]: > I was thinking about how to bring the lzma package more up to date, > but I’m scared to do anything for fear of breaking squashfs-lzma. :) > So I thought I’d write for advice. > squashfs is a read-only compressed filesystem. Currently a kernel > module for reading LZMA-compressed squashfs 3.x is packaged for Debian > through the lzma source package. I think the userspace support is in > squashfs-tools, though I’m not sure since I’ve never tried it. > Good news: squashfs maintainer Phillip Lougher is pushing for > LZMA support in squashfs 4.0 in the mainline kernel v2.6.33 or so. [1] > Packaging this for Debian would perhaps mean backporting the change > for the linux-2.6 package and making sure the squashfs-tools package > has the appropriate support. > 1. How to support current users until an updated kernel enters sid? > Should the lzma package have to continue to produce an lzma-source > package? > I am not excited about making sure this still works with each LZMA > SDK upgrade. squashfs-lzma upstream used to just pick one version > to support (now the version in the mainline kernel is used), and > I’m afraid having to rebase the patch for each release would slow > things down a lot. Assuming Squeeze will be released with kernel 2.6.32 and squashfs/lzma will reach mainline not before 2.6.33 it might be worth the effort to provide an according squashfs 4/lzma + squashfs-lzma-tools toolchain. > 2. Once squashfs 4 + lzma is available, is there a need to continue > to support squashfs 3 + lzma? > I am hoping not, because it is not clear the current kernel > patches apply to recent kernels. But if there is, we can probably > find some way. I personally don't think it's necessary to provide long-term support for squashfs 3 + lzma once squashfs 4 + lzma is available, though I'm not sure what other people think about it. > 3. More generally, what do people use squashfs-lzma for, and what > guarantees do they need in order to do it? We at grml (http://grml.org/) use it for compressing the entire rootfs. Thanks to better compression of lzma (compared to zlib) squashfs-lzma allows us to provide more software on the same ISO size, though the build time clearly increases. If you're interested in some stats: http://grml.org/grml-live/#lzma-vs-zlib > I am hoping some squashfs-lzma user can explain how and perhaps take > on the task of assuring it is well supported for squeeze. But there > is plenty to do short of that, and I would be glad to help your > efforts in any way I can. Thanks for your efforts. JFYI: We (the grml team) have working squashfs 4 + lzma patches for kernel 2.6.31 and an according squashfs-tools package providing lzma support. Please let me know if we can assist in any way. regards, -mika- -- http://michael-prokop.at/ || http://adminzen.org/ http://grml-solutions.com/ || http://grml.org/
Attachment:
signature.asc
Description: Digital signature