LVM and VxVM

Physical extend allocation for /sand

 
SoorajCleris
Honored Contributor

Physical extend allocation for /sand

Hi

Please see this and kindly tell me , will the system boot from the second disk ( c3t2d0s2).

The PE allocation is 424.

# lvdisplay -v /dev/vg00/lvol1
--- Logical volumes ---
LV Name /dev/vg00/lvol1
VG Name /dev/vg00
LV Permission read/write
LV Status available/syncd
Mirror copies 1
Consistency Recovery MWC
Schedule parallel
LV Size (Mbytes) 576
Current LE 18
Allocated PE 36
Stripes 0
Stripe Size (Kbytes) 0
Bad block off
Allocation strict/contiguous
IO Timeout (Seconds) default

--- Distribution of logical volume ---
PV Name LE on PV PE on PV
/dev/dsk/c2t1d0s2 18 18
/dev/dsk/c3t2d0s2 18 18

--- Logical extents ---
LE PV1 PE1 Status 1 PV2 PE2 Status 2
00000 /dev/dsk/c2t1d0s2 00000 current /dev/dsk/c3t2d0s2 00424 current
00001 /dev/dsk/c2t1d0s2 00001 current /dev/dsk/c3t2d0s2 00425 current
00002 /dev/dsk/c2t1d0s2 00002 current /dev/dsk/c3t2d0s2 00426 current
00003 /dev/dsk/c2t1d0s2 00003 current /dev/dsk/c3t2d0s2 00427 current
00004 /dev/dsk/c2t1d0s2 00004 current /dev/dsk/c3t2d0s2 00428 current
00005 /dev/dsk/c2t1d0s2 00005 current /dev/dsk/c3t2d0s2 00429 current
00006 /dev/dsk/c2t1d0s2 00006 current /dev/dsk/c3t2d0s2 00430 current
00007 /dev/dsk/c2t1d0s2 00007 current /dev/dsk/c3t2d0s2 00431 current
00008 /dev/dsk/c2t1d0s2 00008 current /dev/dsk/c3t2d0s2 00432 current
00009 /dev/dsk/c2t1d0s2 00009 current /dev/dsk/c3t2d0s2 00433 current
00010 /dev/dsk/c2t1d0s2 00010 current /dev/dsk/c3t2d0s2 00434 current
00011 /dev/dsk/c2t1d0s2 00011 current /dev/dsk/c3t2d0s2 00435 current
00012 /dev/dsk/c2t1d0s2 00012 current /dev/dsk/c3t2d0s2 00436 current
00013 /dev/dsk/c2t1d0s2 00013 current /dev/dsk/c3t2d0s2 00437 current
00014 /dev/dsk/c2t1d0s2 00014 current /dev/dsk/c3t2d0s2 00438 current
00015 /dev/dsk/c2t1d0s2 00015 current /dev/dsk/c3t2d0s2 00439 current
00016 /dev/dsk/c2t1d0s2 00016 current /dev/dsk/c3t2d0s2 00440 current
00017 /dev/dsk/c2t1d0s2 00017 current /dev/dsk/c3t2d0s2 00441 current
===================================

# model
ia64 hp server rx2600
============================
# uname -a
HP-UX rx260-03 B.11.23 U ia64 3267805133 unlimited-user license
===============================
# pvdisplay -v /dev/dsk/c3t2d0s2
--- Physical volumes ---
PV Name /dev/dsk/c3t2d0s2
VG Name /dev/vg00
PV Status available
Allocatable yes
VGDA 2
Cur LV 8
PE Size (Mbytes) 32
Total PE 4346
Free PE 3922
Allocated PE 424
Stale PE 0
IO Timeout (Seconds) default
Autoswitch On
Proactive Polling On

--- Distribution of physical volume ---
LV Name LE of LV PE for LV
/dev/vg00/lvol1 18 18
/dev/vg00/lvol2 64 64
/dev/vg00/lvol3 12 12
/dev/vg00/lvol4 7 7
/dev/vg00/lvol5 1 1
/dev/vg00/lvol6 144 144
/dev/vg00/lvol7 96 96
/dev/vg00/lvol8 82 82

--- Physical extents ---
PE Status LV LE
00000 free 00000
00001 free 00000
00002 free 00000
00003 free 00000
00004 free 00000
00005 free 00000
00006 free 00000
00007 free 00000
00008 free 00000
00009 free 00000
00010 free 00000
00011 free 00000
00012 free 00000
00013 free 00000
00014 free 00000
00015 free 00000
00016 free 00000
00017 free 00000
00018 current /dev/vg00/lvol2 00000
00019 current /dev/vg00/lvol2 00001
00020 current /dev/vg00/lvol2 00002
00021 current /dev/vg00/lvol2 00003
00022 current /dev/vg00/lvol2 00004
00023 current /dev/vg00/lvol2 00005
00024 current /dev/vg00/lvol2 00006
00025 current /dev/vg00/lvol2 00007
00026 current /dev/vg00/lvol2 00008
00027 current /dev/vg00/lvol2 00009
00028 current /dev/vg00/lvol2 00010
00029 current /dev/vg00/lvol2 00011
00030 current /dev/vg00/lvol2 00012
00031 current /dev/vg00/lvol2 00013
00032 current /dev/vg00/lvol2 00014
00033 current /dev/vg00/lvol2

---------------------

trimmed
---------------

00418 current /dev/vg00/lvol8 00076
00419 current /dev/vg00/lvol8 00077
00420 current /dev/vg00/lvol8 00078
00421 current /dev/vg00/lvol8 00079
00422 current /dev/vg00/lvol8 00080
00423 current /dev/vg00/lvol8 00081
00424 current /dev/vg00/lvol1 00000
00425 current /dev/vg00/lvol1 00001
00426 current /dev/vg00/lvol1 00002
00427 current /dev/vg00/lvol1 00003
00428 current /dev/vg00/lvol1 00004
00429 current /dev/vg00/lvol1 00005
00430 current /dev/vg00/lvol1 00006
00431 current /dev/vg00/lvol1 00007
00432 current /dev/vg00/lvol1 00008
00433 current /dev/vg00/lvol1 00009
00434 current /dev/vg00/lvol1 00010
00435 current /dev/vg00/lvol1 00011
00436 current /dev/vg00/lvol1 00012
00437 current /dev/vg00/lvol

Regards,
Sooraj
"UNIX is basically a simple operating system, but you have to be a genius to understand the simplicity" - Dennis Ritchie
15 REPLIES 15
Fabio Ettore
Honored Contributor

Re: Physical extend allocation for /sand

Hi Sooraj,

I think your system WON'T boot from the second disk because /stand is not on the first position on mirrored disk.
You should always mirror lvols of vg00 with first lvol1, then lvol2 and lvol3 and then other ones.
However you I see unexplained free extents on the top of c3t2d0s2, they are 18 extents exactly as the size of /stand, so I suppose once the /stand was mirrored in the correct order.

I suggest reducing mirror of lvol1 and extending it again onto c3t2d0s2, I presume the first 18 extents of the second disk will be taken.
After that I suggest also issuing lvlnboot -R.

HTH.

Best regards,
Fabio
WISH? IMPROVEMENT!
Roopesh Francis_1
Trusted Contributor

Re: Physical extend allocation for /sand

The sequence should be in correct for root vg in PV.
It should be
First,/dev/vg00/lvol1,/dev/vg00/lvol2,/dev/vg00/lvol3,/dev/vvg00/lvol4 and /dev/vg00/lvol5.
So better re-mirror the Logical volumes and try to boot from ALT disk.

Thanks,
James R. Ferguson
Acclaimed Contributor

Re: Physical extend allocation for /sand

Hi:

As mentioned, at least lvol1, lvol2 and lvol3, in that order, must be mirrored for a boot disk to function.

It is, in my opinion, a hugh mistake _not_ to mirror every logical volume of vg00 in order. After all, if you have a mirrored disk of vg00 fail you certainly want _all_ of the data that is protected on the remaining physical volume (or volumes) to be available! If you booted but lacked the logical volume's like '/usr' what would you do?

Regards!

...JRF...
R.K. #
Honored Contributor

Re: Physical extend allocation for /sand

Hi Sooraj,

The server should NOT boot from this disk as /stand, primary swap, and / must be contiguous.

Because it is used by the boot loader, /stand must be the first file system on a physical disk and it must be contiguous and non-relocatable.
Also the firmware does not understand LVM nor VxVM. So that it would get bootable kernel first in ideal cases.

But this is not true in your case.

Regds..
Don't fix what ain't broke
TTr
Honored Contributor

Re: Physical extend allocation for /sand

There is a specail mirroring process for boot devices. As noted above the first boot device was mirrored ad-hoc to another disk.

To show the boot status of the disks, run the command "lvlnboot -v" and post the output.
SoorajCleris
Honored Contributor

Re: Physical extend allocation for /sand

Hi everyone..

Thank you so much for the reply and the suggetions.. I understand .. :)

The output I have pasted here is after doing some RnD.. I surprised that, the system booted from the second disk where the stand is after lvol8.. I dont know how LABEL file managed to read it.

The activity done was.

1. Mirrored the disk.. done everything. checked . It was booting.

2. Using #lvsplit , splited the lvol1 .

3. Mirrored ( lvextend -m 1) again lvol1 with second disk again. ( can see the last 18 PEs)

4. used lvremove to remove lvol1b ( splitted one) - so that you can see the free space, 1st 18 PEs.

updated

lvlnboot -R

----------------------

Rebooted using second path -- the system booted !!!!!!!!!!!!!
----------------------------

Making sure, I have removed all the first copy ( mirror). and remove the first disk ( primary disk) from the VG also.

Now it didnt boot !!! :)

what do you think? How the system booted when the primary was available? Was the LABEL reading from the first disk itself??

If anyone have test server , can you try this ?

Regards
sooraj

"UNIX is basically a simple operating system, but you have to be a genius to understand the simplicity" - Dennis Ritchie
Fabio Ettore
Honored Contributor

Re: Physical extend allocation for /sand

Hi,

sorry, but I'm still doubtful that your system booted from the second disk. Do you have a complete log of that boot phase?
I'd think that your system didn't boot from the second disk, rather it failed and the system tried on its own to boot from the primary one instead (by the autosearch option enabled, see the WARNINGS section from man setboot).

I'd think so also because, if I've understood well your last actions, the system didn't boot when removing the first disk. That should have worked if the second disk was correctly bootable.

Definitely I think your system only boots by the primary disk and you should solve the mirror copies of lvol1, lvol2 and lvol3 on the second disk to have the right sequence as already mentioned.

Best regards,
Fabio
WISH? IMPROVEMENT!
Torsten.
Acclaimed Contributor

Re: Physical extend allocation for /sand

The system is booting the OS loader (hpux.efi in this case) from a given disk and loads the kernel. Then it is activating vg00.

From now on you cannot tell were the system reads the data, first or second disk. It is just using the mirrored LVOLs.

If autosearch is on, the system will try the next boot path if the first doesn't work. So are you really sure it worked with the first disk or did it switch to the next?

Hope this helps!
Regards
Torsten.

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TTr
Honored Contributor

Re: Physical extend allocation for /sand

There is no mention of boot sector of the alternate disk. That's why I asked for the "lvlnboot -v" output. The "lifls /dev/dsk/c3t2d0s2" would also show what is in the boot sector of the alt disk. Of course the true check for the bootability of a dsik is actually booting from it and confirming that the server indedd booted from the alt disk as indicated above.