On Sun, Mar 7, 2021 at 7:03 AM Dave Sherohman <d...@sherohman.org> wrote:
> On Wed, Mar 03, 2021 at 10:28:34AM -0500, Marc Auslander wrote: > > One potential gotcha. When you boot from an mdadm file system containing > > /boot/grub, grub will not write to the file system. In particular, it > will > > not update grub/grubenv even if you have a save_env line in grub.cfg. > So if > > you use grub-reboot to specify an alternate line in grub.cfg, you need to > > reset grubenv afterwards. I do this in a root @reboot cron job. > > > > If you don't know what I'm talking about, you probably don't need to > worry > > about this. > > I don't *know* know what you're talking about, but I think I get the > gist of it. I'm not doing anything fancy enough to have to deal with > the details of grubenv and grub-reboot, but your initial comment about > grub refusing to write to a mdadm filesystem is consistent with what I > was seeing, and it's nice to have confirmation that it actually does > work that way. > Dave the issues you describe dealing with mdadm setup, well that's why I eventually just switched to LVM-based mirroring and striping. Early on, LVM wasn't supported as a boot volume, but the original code base had supported that on HP-UX and AIX. So years ago now, that restriction was lifted. Another mdadm issue is just the use of it in a kind of "oral tradition": it's not that setup is hard, it just still seems like magic spells after all this time. -- > Dave Sherohman > >
