Chris Murphy wrote:
In that case, wouldn’t it be more precise to say: CentOS-7 doesn’t support dual boot if you are using LVM?
It seems to me to work reasonably well with ext4. Does it work with LVM if you have a separate ext4 /boot partition?
Or using Windows or OS X (just an ugly failure in that it causes XNU
to panic, but it hasn’t actually injured anything, it is still possible to boot OS X via the firmware boot manager).
Correct. If the existing OS uses ext3/4 on standard partitions, then the installer can do fs shrink, and when it calls grub2-mkconfig, the installation is found and boot entries are created for it. That the boot entry is distinctly sub-optimal is a long standing GRUB problem not an installer problem and not a CentOS problem per se. But it’s still sloppy. The tools already exist for this to be done better, but for reasons unknown GRUB upstream likes to do things the hard and sub optimal way whenever possible.
No. The root fs is hidden in an inactive LV, so os-prober (via grub2-mkconfig) won’t find that Linux installation. The installer should make all LVs active so os-prober can find other OS’s and make boot entries for them, but it doesn’t.