Re: Re: Re: grub2-install: Couldn't find physical volume ‘(null)’.

[Sam Varshavchik]

Andrei Borzenkov writes:

> On Mon, Apr 11, 2016 at 1:56 PM, Sam Varshavchik <address@hidden>  
> wrote:
> >> > address@hidden ~]# /sbin/grub2-install /dev/sdb
> >> > Installing for i386-pc platform.
> >> > /sbin/grub2-install: warning: Couldn't find physical volume ‘(null)’.
> >> > Some modules may be missing from core image..
> >> > /sbin/grub2-install: warning: Couldn't find physical volume ‘(null)’.
> >> > Some modules may be missing from core image..
> >> > Installation finished. No error reported.
> >> >
> >> > Now, anyone have any idea what's up with these warnings?
> >> >
> ...
> >
> > Googling around finds some references of this warning coming out while the
> > md-raid volumes are being synced. This warning still comes out after
> > everything is fully synced up.
> >
>
> I think I know what happens. Did you reboot after MD was resynced? If
> not, please try
>
> blockdev --flushbufs /dev/sda
> blockdev --flushbufs /dev/sdb
>
> and try grub2-install once again.

I did not reboot, but this did not make any difference.

address@hidden ~]# blockdev --flushbufs /dev/sda
address@hidden ~]# blockdev --flushbufs /dev/sdb
address@hidden ~]# /sbin/grub2-install /dev/sdb
Installing for i386-pc platform.
/sbin/grub2-install: warning: Couldn't find physical volume ‘(null)’. Some  
modules may be missing from core image..
/sbin/grub2-install: warning: Couldn't find physical volume ‘(null)’. Some  
modules may be missing from core image..
Installation finished. No error reported.

This may or may not be related, but in the output of mdadm --detail I posted  
previously: two of assembled arrays consist of units numbered 1 and 2:

          Name : monster:0
          UUID : 7ae940a5:bd5a0d0f:666adf78:e0c5b498
        Events : 1188

   Number   Major   Minor   RaidDevice State
      2       8       17        0      active sync   /dev/sdb1
      1       8        1        1      active sync   /dev/sda1


          Name : monster:1
          UUID : 067004a2:11daf9c2:0cedca66:ac63c62d
        Events : 1127

   Number   Major   Minor   RaidDevice State
      2       8       18        0      active sync   /dev/sdb2
      1       8        2        1      active sync   /dev/sda2

And the two others are numbered 2 and 3:

          Name : monster:2
          UUID : b0cb9b26:be362a98:012cdf18:19de5ac1
        Events : 59413

   Number   Major   Minor   RaidDevice State
      3       8       19        0      active sync   /dev/sdb3
      2       8        3        1      active sync   /dev/sda3

          Name : monster:3
          UUID : ac2446aa:661a4977:0960a296:6d0b48c3
        Events : 165897

   Number   Major   Minor   RaidDevice State
      3       8       21        0      active sync   /dev/sdb5
      2       8        5        1      active sync   /dev/sda5

pgpzCdcO1w7cC.pgp
Description: PGP signature