Conference aosg::lsm

776.0. "LSM mirrored root recover without reencapsulating?" by UTOPIE::FRUEHWIRTH_B () Fri Mar 28 1997 10:30

Hi!

I read some notes about LSM root recovery and all talk about un-encapsulating 
the rootvol and removing all pointers (fdmns, fstab ...) to the rootvol and so
on.

I'm now in the situation that a customers mirrored root filesystem needs to 
be vdumped and vrestored because of an advfs inconsistency (a "lost file" 
that can't be deleted) and ask myself, what's wrong if I do the following:

system disks are rz0 and rz1. operating system version is V3.2d-1.

- shutdown system
- physically remove rz1 from the system.
- boot single user, start lsm
- rz1 will be seen as failed
- shutdown system
- boot from cd
- make device for rz0 and tape, mkfdmn and mkfset for root_domain on rz0a   
- mount root-domain and restore from tape
- halt system
- reboot from rz0, ensure lsm starts ok.
- shutdown system
- put rz1 back to the system
- boot from rz0
- volrecover

I tried this yesterday and it worked well except that I had to decrease the 
size of the a partition by 16 before the mkfdmn because it has been increased 
during the volrootmir and the increased size did not match the size 
of the root volume. (I did increase the size again after the vrestore).

Did I miss something that can cause problems when doing this that way?

Thanks and regards,

	Birgit

    Birgit,
    
    Your procedure looks good to me. I think the notes you refer to are
    requesting the removal of the LSM pointers in /etc/sysconfigtab,
    /etc/fstab and /sbin/swapdefault because the LSM config was destroyed
    or removed (bad disk replacement).
    
    So, as long as your LSM config is existing and intact on the disk you
    restore from tape, it should go.
    
    Regards, Manu.

    Thanks, Manu. Now I feel better, when doing the restore this way 
    at the customer site.
    
    Regards,
    	Birgit