Using CD #1 to install. Probably won’t work with netinst CD [no kernel image package; confirm].
Picked install at the menu (normal, not advanced)
Language, keyboard, blah blah blah.
Partitioning method: manual
First disk, one partition, size max, physical volume for LVM
SHORTCUT:
configure LVM, yes, alt-f2 for console
sfdisk -d /dev/vda | sfdisk /dev/vdb (etc.)
alt-f1, go back
configure LVM, yes
create vg, give name, select all
GET DM-RAID MODULE:
alt-f2 for console
cd /tmp
ar x /cdrom/pool/main/l/linux-image-*.deb data.tar.xz
xzcat data.tar.xz | tar x
depmod -a -b /tmp
modprobe -d /tmp dm-raid
CREATE RAIDed LV
lvcreate --type raid5 -i 4 -I 256 -L 10G -n root vg0 (note: -l 256 picked out of thin air… hoping larger size speeds up on the weird VM setup)
PROBLEM: wheezy lvm does not support raid10 (for swap). SOLUTION: use multiple RAID-1s
NOTE: Have to tell it what PVs to use, else it puts them both on the same disks.
lvcreate --type raid1 -m1 -L 1G -n swap0 vg0 /dev/vda1 /dev/vdb1
lvcreate --type raid1 -m1 -L 1G -n swap1 vg0 /dev/vdc1 /dev/vdd1
alt-f1 to get back to installer, select ‘finish’ (on the LVM menu)
Observe now suddenly have tons of LVs showing. Silly installer, most of those should be hidden. Ignore the ones with ‘rimage’ and ‘rmeta’ in their names.
Select LV root, use as ext4 (or whatever), mount point /, done
Select LV swap0, use as swap, done
Select LV swap1, use as swap, done
Finish & write changes to disk, yes
Wait for base system to install. (NOTE: Can watch progress on alt-f4).
Pick whatever for scan another CD and network mirror.
Package usage survey is up to you. Same with software to install.
When asked, install GRUB to the MBR.
PROBLEM: On wheezy, this fails (grub-install gives you a grub-probe command to capture the output of for a bug report, running it gives “grub-probe: info: unknown LVM type raid5” buried in the mess). Requires grub2 2.0 (per Google), which isn’t in Wheezy.
SOLUTION: Locally built a backport. Build was trivial; just grabbed the source package, dch -l +asd, installed build-deps, build. (Not needed on jessie, of course.)
alt-f2
chroot /target /bin/bash
mount /sys
dpkg -i grub-pc_*.deb grub-pc-bin_*.deb grub-common_*.deb grub2-common_*.deb
grub-install /dev/vda … grub-install /dev/vd
echo ‘dm_raid’ >> /etc/initramfs-tools/modules
update-initramfs -kall -u
update-grub (untested; see problem below)
umount /sys
exit
alt-f1
Continue without a boot loader. Ignore the ‘no boot loader installed’ message.
Continue at the installation complete message.
PROBLEM: no grub config. Booted by specifying at grub prompt.
linux /boot/vmlinuz-3.2.0-4-amd64 root=/dev/mapper/vg0-root
initrd /boot/initrd.image-3.2.0-4-amd64
boot
SOLUTION: added an update-grub above, suspect that will entirely fix. Did after the boot.
Make sure dm-raid module loads in initramfs
Fix swap priorities in fstab (make them both the same)
PROBLEM: wheezy lvs does not know how to display raid5 sync completion. It does display for raid1 (jessie does both). SOLUTION: dmsetup status shows it, it’s the final column. A little less friendly, but usable.
PROBLEM: lvextend doesn’t work on raid5 LV on wheezy. Suspect it doesn’t on jessie either; dm-raid does not do reshape, per even 3.16 kernel docs. SOLUTION: none
dm-raid docs: https://www.kernel.org/doc/Documentation/device-mapper/dm-raid.txt
lvm2-raid: https://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/doc/lvm2-raid.txt?cvsroot=lvm2