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Re: Mirrored boot disk and dump device

 
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Rainer von Bongartz
Honored Contributor

Mirrored boot disk and dump device


having a mirrored boot disk with following layout

Boot Definitions for Volume Group /dev/vg00:
Physical Volumes belonging in Root Volume Group:
/dev/dsk/c6t0d0 (255/255/0/0.0) -- Boot Disk
/dev/dsk/c13t0d3 (0/0/10/0/0.1.1.0.0.0.3) -- Boot Disk
/dev/dsk/c15t0d3 (0/0/10/0/0.1.10.0.0.0.3) -- Boot Disk
Boot: lvol1 on: /dev/dsk/c6t0d0
/dev/dsk/c13t0d3
/dev/dsk/c15t0d3
Root: lvol3 on: /dev/dsk/c6t0d0
/dev/dsk/c13t0d3
/dev/dsk/c15t0d3
Swap: lvol2 on: /dev/dsk/c6t0d0
/dev/dsk/c13t0d3
/dev/dsk/c15t0d3
Dump: lvol2 on: /dev/dsk/c6t0d0, 0


I booted from 0/0/10/0/0.1.10.0.0.0.3 (/dev/dsk/c15t0d3) so I expected that the dump device lvol2 would be on this disk an not on dev/dsk/c6t0d0

As I plan to remove the disk at /dev/dsk/c6t0d0
I wonder if I got anything wron with the boot disk

He's a real UNIX Man, sitting in his UNIX LAN making all his UNIX plans for nobody ...
3 REPLIES 3
Solution

Re: Mirrored boot disk and dump device

No I don't think so...

The dump process is not "aware" of LVM - basically it has to be a very simple bit of code to dump out the contents of memory to disk - making it LVM aware would add complexity and risk (what if the failing kernel code that caused a panic was in the LVM device driver?). That's why dunp devices have to be contiguous because allthough you tell it vthe dumnp device in LVM format (using the lvlnboot command), this is just stored for dump purposes as a device and an offset.

So when a dump occurs, it doesn't write out to the mirror.

If you want to remove the device c6t0d0 from the root VG, you'll need to:

lvrmboot -d lvol2 /dev/vg00
(not sure if you will have to do some lvreduce operations here to get rid of mirrors on that disk...)
vgreduce /dev/vg00 /dev/dsk/c6t0d0
lvlnboot -d /dev/vg00/lvol2

HTH

Duncan

I am an HPE Employee
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Ganesan R
Honored Contributor

Re: Mirrored boot disk and dump device

Hi,

It looks you have two way mirroring. So the dump device will be the swap lvol from where the system booted.

After you reduced all the mirrors from c6t0t0 and removed the disk from vg00 run lvlnboot -vR which recover any missing links to all of the logical volumes BDRA.

Best wishes,

Ganesh.
Rainer von Bongartz
Honored Contributor

Re: Mirrored boot disk and dump device

Thanxs guys, that's the way it worked
He's a real UNIX Man, sitting in his UNIX LAN making all his UNIX plans for nobody ...