EMC boot disk

[Simeon Harwood]

Morning all,
Anyone come accross this before. We upgraded our SAN fabric the other day and some hardware paths have changed from the HP box end.
One machine boots from the EMC symetrix. We're using pv links, so we have got pri and alt path for the boot disk. After the upgrade, we tried to boot to the pri path, but it was not found, due to hardware path changing, so we booted to the alt path. This booted OK, but, vg00 still has the old disk in it.
Is there a supported method to get the old disk out, and the new one in. On any other volume group, you can just export and re-import the vg, but this is the boot volume group.
Any help appreciated.

Sime.

[RAC_1 · Accepted solution]

First check, if you get following right.

vgexport -psv -m /tmp/vg00.map /dev/vg00

vgimport -psv -m /tmp/vg00.map /dev/vg00

If this goes well, you can import the vg00 with new disks. I think you will have to boot into single user mdoe for this. (When actually doing it, remove -p option.)

[Simeon Harwood]

Hi,

good plan. I've been trying this on a test machine but with no success.
I've got a boot disk that I have physically moved to another slot to change the hardware address, and trying to use the method that you suggested. I got vg00 exported and imported, but when I try to boot, the machine panics. DOH!!!
I put the disk back into the original slot and it booted OK.
So i'm still with no solution, any more suggestions please.

Sime.

[RAC_1]

If you know the hardware address (of new slot, where you plugged in disk), then it is easy.

Boot into single user mode and vgexport vg00.
vgexport -v -m /tmp/vg00.map /dev/vg00

(Take backup copies of /etc/lvmconf/* files nd lvdisplay,bdf,vgdisplay outputs)

mkdir /dev/vg00
mknod /dev/vg00/group c 64 0x000000
Prepare file called vg00.pvlist and put all disks that belong to vg00. Including disk that you put in another slot.

vgimport -m /tmp/vg00.map -f vg00.pvlist /dev/vg00
vgchange -a y vg00
mountall
Check. This should do it.

[Steven E. Protter]

Shalom Simeon,

When the SAN upgrade happened, the physical path to the disks all got changed.

I think to re-establish boot you need to detect what the new boot path is.

You should be able to get it by interupting the boot process at the 10 second prompt and running sea.

What you will find is the path to the boot disk is different that your output from the lvlnboot command run prior to the SAN upgrade.

You are kind of in a Chicken or egg situation but you should be able to use the bo command to boot off one of the new disk paths. Then you will need to update your boot configuration.

I'm posting a general procedure that covers mirroring. you probably only need the last few steps.

pvcreate -B /dev/rdsk/c1t0d0 #use real disk

mkboot -l /dev/rdsk/c1t0d0
mkboot -a "hpux -lq (;0)/stand/vmunix" /dev/rdsk/c1t0d0 # use real disk


# mkboot -b /usr/sbin/diag/lif/updatediaglif -p ISL -p AUTO -p HPUX -p PAD -p LABEL /dev/rdsk/c?t?d?

If you are running 64-bit OS:

# mkboot -b /usr/sbin/diag/lif/updatediaglif2 -p ISL -p AUTO -p HPUX -p PAD -p LABEL /dev/rdsk/c?t?d?


vgextend /dev/vg00 /dev/dsk/c1t0d0 # same thing
lvextend -m 1 /dev/vg00/lvol1 /dev/dsk/c1t0d0

# real disk. repeat for other lvols

lvlnboot -r /dev/vg00/lvol3 # root fs /
lvlnboot -s /dev/vg00/lvol2 #swap
lvlnboot -d /dev/vg00/lvol2 #swap/dump
lvlnboot -b /dev/vg00/lvol1
lvlnboot -R
lvlnboot -v
setboot
setboot -a 52.1.0 # second disk

I think you should run the lvlnboot and setboot series.

Note, this is why i always avoid booting off a SAN. Bottom line here is that things can change suddenly and then your system won't boot or start properly.

Even without a SAN I've endured a loss of SAN disaster and would have had to rebuild systems from Ignite tape had they booted off the thing.

SEP

[Darrel Louis]

Hi,

I think steven is wright.
Could it be that the Fibre Cables where switched, this will cause a different HW-Path? As LVM can't handle this.

Darrel

[Simeon Harwood]

Thanks a lot RAC and SEP. I have to use pieces of both methods to get this to work. Bellow is the method I used.
Thanks again for the help, it's got me out of a tight spot.
Sime.

interupt boot of server.
boot to disk devive with OS on it and interact with ISL
hpux -lm
cd /tmp
echo "/dev/dsk/c1t2d0" > vg00.pvlist
vgexport -p -s -m vg00.map vg00
vgexport vg00
cd /dev
mkdir vg00
cd vg00
mknod group c 64 0x000000
cd /tmp
vgimport -m vg00.map -f vg00.pvlist
cd /etc
rm lvmtab
vgscan -a -v
vgchange -a y vg00
vgdisplay -v vg00
lvlnboot -v
lvlnboot -r /dev/vg00/lvol3 # root fs /
lvlnboot -s /dev/vg00/lvol2 #swap
lvlnboot -d /dev/vg00/lvol2 #swap/dump
lvlnboot -b /dev/vg00/lvol1
lvlnboot -R
lvlnboot -v

vgchange -a n vg00
setboot
setboot -a 8/0.14 # second disk
reboot