=РЕШЕНИЕ=
после замены диска ждем окончания синхронизации
root@ubuntu:~# cat /proc/mdstat
Personalities : raid1 linear multipath raid0 raid6 raid5 raid4 raid10
md127 : active raid1 sdb1[2] sda1[0]
10475520 blocks super 1.2 [2/1] [U_]
[>....................] recovery = 1.1% (116736/10475520) finish=4.4min speed=38912K/sec
unused devices: <none>
root@ubuntu:~# cat /proc/mdstat
Personalities : raid1 linear multipath raid0 raid6 raid5 raid4 raid10
md127 : active raid1 sdb1[2] sda1[0]
10475520 blocks super 1.2 [2/2] [UU]
unused devices: <none>
готово
root@ubuntu:~# for disk in sd{a,b} ; do grub-install --recheck /dev/$disk ; done
Installing for i386-pc platform.
grub-install: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
grub-install: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
Installation finished. No error reported.
Installing for i386-pc platform.
grub-install: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
grub-install: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
Installation finished. No error reported.
перезагрузка (этот пункт обязателен)
root@ubuntu:~# for disk in sd{a,b} ; do grub-install --recheck /dev/$disk ; done
Installing for i386-pc platform.
Installation finished. No error reported.
Installing for i386-pc platform.
Installation finished. No error reported.
если не перезагружаться, то ошибка grub-install: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. так и будет вылазить.