On Wed, May 10, 2017 at 05:24:48PM +0200, Wouter Verhelst wrote: > On Sat, May 06, 2017 at 03:35:52PM +0100, Sam Kuper wrote: > > On 06/05/2017, Ian Campbell <ijc@debian.org> wrote: > > > It would in theory be possible to arrange build and install modules > > > during installation using the in-progress target installation (where > > > the normal toolchain packages could be installed) such that they are > > > available during the latter parts of the install procedure -- that is > > > clearly of limited use for any modules which are required for the > > > filesystems which you want to install to (certainly the root fs and > > > perhaps any separate /usr or /var partition(s)). > > > > Given that a machine intended to run ZFS is likely to be provisioned > > with >2GB of RAM (much more than the Debian Installer would normally > > require), might a viable workaround be for the Debian Installer to > > take the following steps? > > > > - Ensure that some minimum amount of RAM is available, and refuse to > > proceed with a root-on-ZFS installation if not; > > > > - install the toolchain, ZFS source, and any other packages from > > "main" or "contrib" necessary to support these, to a RAM disk; > > > > - compile and load ZFS functionality; > > Add partitioning here, and add an extra partition used for holding the debootstrap system. [1] > > - format the target HDD/SSD using ZFS; > > > > - copy the toolchain binaries and ZFS source packages, etc, to the > > relevant places on the target HDD/SSD (/usr/bin , > > /var/cache/apt/archives/ , etc); > > > > - resume the installation as usual. Before installing the bootloader, check if it's a ZFS installation, and if so, then replicate the debootstrapped system from the extra partition to the ZFS dataset marked as rootfs, using something that supports --numeric-owner. [2] Then delete the extra partition, expand the ZFS one to the end of the device. eg: [1] sda1: 256MB /boot sda2: 930GB zfs-vdev And then the installer substracts 4GB from sda2, creates sda3 for debootstrap, and takes care of the removal transparently. Using this method, sda2 only gets expanded to the size that is requested, instead of the whole disk--allows underprovisioning. > I don't see why not. We already need the ability to run debootstrap; > this would just change that to a need to do so twice. > > It wouldn't be terribly efficient for a netinstall, since it requires > that you download the base system twice; but it could imagine a special > "non-free netinstall" image which would contain zfs-dkms and its > dependencies on top of the base system, so that you don't need to > download things more than once. I'm not sure if [2] is the right place in the installation sequence for this, but it seems like something like this method could make efficient use of bandwidth for a netinstall :-) Cheers, Nicholas
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