topic Re: Question about Mirror Setup in Operating System - HP-UX

Question about Mirror Setup

Daniel Schneider_3 — Tue, 26 Aug 2003 11:22:31 GMT

Hi all,

is there anybody who can tell me, if my mirrorsetup is right?
I gave the machine a second hard disk, added it to the volume group, and defined all volumes that their mirror is on separate disk. Then I increased the number of mirrors for each volume from 0 to 1, except /, /stand and swap, because of the message 'lvlnboot: Boot volume should be the first logical volume on the physical volume' respective for root (/):'lvlnboot: LIF information corrupt or not present on /dev/dsk/c3t15d0. Use mkboot command to initialize the LIF area'.
Do I need those Mirrors anyway?

# vgdisplay -v
--- Volume groups ---
VG Name /dev/vg00
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 8
Open LV 8
Max PV 16
Cur PV 2
Act PV 2
Max PE per PV 4350
VGDA 4
PE Size (Mbytes) 8
Total PE 8680
Alloc PE 4059
Free PE 4621
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vg00/lvol1
LV Status available/syncd
LV Size (Mbytes) 304
Current LE 38
Allocated PE 38
Used PV 1

LV Name /dev/vg00/lvol2
LV Status available/syncd
LV Size (Mbytes) 1024
Current LE 128
Allocated PE 128
Used PV 1

LV Name /dev/vg00/lvol3
LV Status available/syncd
LV Size (Mbytes) 200
Current LE 25
Allocated PE 25
Used PV 1

LV Name /dev/vg00/lvol4
LV Status available/syncd
LV Size (Mbytes) 200
Current LE 25
Allocated PE 50
Used PV 2

LV Name /dev/vg00/lvol5
LV Status available/syncd
LV Size (Mbytes) 152
Current LE 19
Allocated PE 38
Used PV 2

LV Name /dev/vg00/lvol6
LV Status available/syncd
LV Size (Mbytes) 1712
Current LE 214
Allocated PE 428
Used PV 2

LV Name /dev/vg00/lvol7
LV Status available/syncd
LV Size (Mbytes) 1832
Current LE 229
Allocated PE 458
Used PV 2

LV Name /dev/vg00/lvol8
LV Status available/syncd
LV Size (Mbytes) 1528
Current LE 191
Allocated PE 382
Used PV 2

...

--- Physical volumes ---
PV Name /dev/dsk/c1t15d0
PV Status available
Total PE 4340
Free PE 1959
Autoswitch On

PV Name /dev/dsk/c3t15d0
PV Status available
Total PE 4340
Free PE 2662
Autoswitch On

Thanks for all help!

Best Regrads
Daniel

Re: Question about Mirror Setup

Chris Wilshaw — Tue, 26 Aug 2003 11:27:28 GMT

To set up the mirroring properly for vg00, you need to create the extra disk using the -B option

eg:

pvcreate -B /dev/rdsk/c3t15d0

Then

mkboot /dev/rdsk/c3t15d0

This is essential as it will allow you to boot your system from the second disk in the event of the first one failing.

Re: Question about Mirror Setup

James R. Ferguson — Tue, 26 Aug 2003 11:32:33 GMT

Hi Daniel:

No, you need to start over. You must 'pvcreate' the physical disk with 'pvcreate -B' to reserve space for the LIF area. You must mirror the logical volumes starting with lvol1, lvol2 and then lvol3. You should continue in sequence, although the first three are the critical ones. In total:

# pvcreate ???B /dev/rdsk/cXtYdZ
# vgextend /dev/vg00 /dev/dsk/cXtYdZ
# mkboot /dev/rdsk/cXtYdZ
# mkboot ???a "hpux ???lq" /dev/rdsk/cXtYdZ
# for LV in 1 2 3 4 5 6 7 8
> do
> lvextend ???m 1 /dev/vg00/lvol${LV} /dev/dsk/cXtYdZ
> done
# lvlnboot ???v

# mkboot ???a "hpux ???lq" /dev/rdsk/cXtYdZ #...for original volume, too???
# setboot ???a [alternate_path] #...for new mirror...
# lifcp /dev/rdsk/xCtYdZ:AUTO - #...copy to stdout for verificati...

...The '-lq' option to 'mkboot' specifies a low quorum. This will allow you to boot if one of the two mirrors is missing. The 'setboot' command insures that a secondary boot path is available, automatically, should the first boot path be defunct.

Regards!

...JRF...

Re: Question about Mirror Setup

Alan Turner — Tue, 26 Aug 2003 11:44:31 GMT

Daniel

If you don't mirror /, /stand and swap, then if your 1st hard disk fails, your
system will fail. Therefore, I'd recommend mirroring those 3 filesystems.
Doing this means extra effort at set-up, because you need to create a boot area. If possible, I'd also advise strict mirror allocation, i.e. create physical volume groups in your root volume.
Best knowledgebase article:
"ISL error occurs when attempting to mirror HP-UX system disk"
ref 12003455439 (typo in step 8, c0t3d0 should be c3t5d0 ?)
other useful ones:
"Creating a mirrored boot disk" ref LVMKBRC00005103
"Replacing an attached strictly mirrored hot swap hard disk"
ref LVMKBRC00006111
"How do I fix the boot message IPL error bad LIF..." ref KBRC00001355

I had a number systems to set up the same way, and wrote myself a script to
do it because of the risk of typos in the repetitive operations. There's also a
titchy bit of LVM maintenance mode set up (you need to disable mirror
recovery , and you might want to change some other filesystems from MWC
to MCR if writes are scattered).

Re: Question about Mirror Setup

Stuart Abramson_2 — Tue, 26 Aug 2003 12:00:41 GMT

Here are the steps to mirror a root disk. For hp-ux 11.0:

1. Build the OS from CDs on the first two left side disks in vg00.
The build process creates the VG, PVs, LVs on disks:

cLt6d0
cLt5d0

2. Install Mirror/UX.

3. Map out what LVs are on what PVs:

# pvdisplay -v /dev/dsk/c4t6d0 | grep lvol | grep "^ /"
/dev/vg00/lvol1 12 12
/dev/vg00/lvol2 468 468
/dev/vg00/lvol3 21 21
/dev/vg00/lvol6 25 25
/dev/vg00/lvol7 138 138
/dev/vg00/lvol12 50 50
/dev/vg00/lvol5 25 25
/dev/vg00/lvol8 127 127
/dev/vg00/lvol9 31 31
/dev/vg00/lvol14 13 13

Make sure you know what is where.

3. Install the mirrors:

a. Mirror the cL disks on the cR disks.

cLt6d0 cRt6d0 (These are boot disks.)
cLt5d0 cRt5d0

b. Type commands:
pvcreate -B /dev/rdsk/cRt6d0 # boot disk mirror
pvcreate /dev/rdsk/cRt5d0
vgextend vg00 /dev/dsk/cRt6do /dev/dsk/cRt5d0
mkboot -l /dev/rdsk/cRt6d0 # boot disk only
mkboot -a "hpux -lq (;0)/stand/vmunix" /dev/rdsk/cRt6d0
lvextend -m 1 /dev/vg01/lvol1 /dev/dsk/cRt6d0
lvextend -m 1 /dev/vg01/lvol2 /dev/dsk/cRt6d0
lvextend -m 1 /dev/vg01/lvol3 /dev/dsk/cRt6d0
lvextend -m 1 /dev/vg01/lvol4 /dev/dsk/cRt6d0
lvextend -m 1 /dev/vg01/lvol5 /dev/dsk/cRt6d0
lvextend -m 1 /dev/vg01/lvol6 /dev/dsk/cRt6d0
...
lvextend -m 1 /dev/vg01/lvol15 /dev/dsk/cRt5d0
...
mirror all LVs in order to the proper disk

lvlnboot -R
lvlnboot -v # Shows boot status

c. Verify Proper Boot String:

# lifcp /dev/dsk/c1t2d0:AUTO -
hpux -lq

# lifcp /dev/dsk/c2t2d0:AUTO -
hpux -lq

If either one is not correct, you can reset it on the fly:

# mkboot -a "hpux -lq" /dev/rdsk/cXtYdZ

d. Verify proper boot disk contents in LIF:

# lifls /dev/dsk/c1t2d0
ODE MAPFILE SYSLIB CONFIGDATA SLMOD2
SLDEV2 SLDRV2 SLSCSI2 MAPPER2 IOTEST2
PERFVER2 PVCU SSINFO HPUX ISL
AUTO LABEL

e. Check server "stable memory". This sets primary and alternate
boot disk paths:

# setboot

Primary bootpath : 0/0/1/1.2.0
Alternate bootpath : 0/0/2/0.2.0

Autoboot is ON (enabled)
Autosearch is ON (enabled)

If any of these are not correct, then you can reset those on the fly
with "setboot".

# setboot -p 0/0/1/1.2.0 -b on
# setboot -a 0/0/2/0.2.0 -b on

Re: Question about Mirror Setup

Steven E. Protter — Tue, 26 Aug 2003 12:27:03 GMT

When you are all done(the prior posts are exactly what I would have advised had I caught this early),

check your setup as follows:

1) lvlnboot -v

Boot Definitions for Volume Group /dev/vg00:
Physical Volumes belonging in Root Volume Group:
/dev/dsk/c1t2d0 (0/0/1/1.2.0) -- Boot Disk
/dev/dsk/c6t8d0 (0/4/0/0.8.0.255.6.8.0)
/dev/dsk/c2t2d0 (0/0/2/0.2.0) -- Boot Disk
Boot: lvol1 on: /dev/dsk/c1t2d0
/dev/dsk/c2t2d0
Root: lvol3 on: /dev/dsk/c1t2d0
/dev/dsk/c2t2d0
Swap: lvol2 on: /dev/dsk/c1t2d0
Dump: lvol2 on: /dev/dsk/c1t2d0, 0

The disks will be different but this is in general what you want.

Then:

lvdisplay -v /dev/vg00/lvol3

The output should look like this:
--- Logical volumes ---
LV Name /dev/vg00/lvol3
VG Name /dev/vg00
LV Permission read/write
LV Status available/syncd
Mirror copies 1
Consistency Recovery MWC
Schedule parallel
LV Size (Mbytes) 1024
Current LE 64
Allocated PE 128
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/c1t2d0 64 64
/dev/dsk/c2t2d0 64 64

--- Logical extents ---
LE PV1 PE1 Status 1 PV2 PE2 Status 2
00000 /dev/dsk/c1t2d0 00288 current /dev/dsk/c2t2d0 00032 current
00001 /dev/dsk/c1t2d0 00289 current /dev/dsk/c2t2d0 00033 current
00002 /dev/dsk/c1t2d0 00290 current /dev/dsk/c2t2d0 00034 current
00003 /dev/dsk/c1t2d0 00291 current /dev/dsk/c2t2d0 00035 current
00004 /dev/dsk/c1t2d0 00292 current /dev/dsk/c2t2d0 00036 current
00005 /dev/dsk/c1t2d0 00293 current /dev/dsk/c2t2d0 00037 current
00006 /dev/dsk/c1t2d0 00294 current /dev/dsk/c2t2d0 00038 current
00007 /dev/dsk/c1t2d0 00295 current /dev/dsk/c2t2d0 00039 current
00008 /dev/dsk/c1t2d0 00296 current /dev/dsk/c2t2d0 00040 current
00009 /dev/dsk/c1t2d0 00297 current /dev/dsk/c2t2d0 00041 current
00010 /dev/dsk/c1t2d0 00298 current /dev/dsk/c2t2d0 00042 current

...

more cut.

Repeat for other logical volumes.

Lastly: You need to test it.

You need to schedule a maintenance window and pull out the primary boot disk and boot off the alternate. That is the only way to be sure.

SEP

Re: Question about Mirror Setup

Daniel Schneider_3 — Tue, 26 Aug 2003 12:57:28 GMT

Thank you Guys for all your great help.
Now it works - as I tested. I'm happy about your help.
I needed to rewind all my doings, and set the second disk to bootable. Than added it to the vg00 again, and startet all the mirrors again.
Then I touched some new files to different filesystems and started the machine from alternative bootpath. It started normally and showed the newly files.

Thank you all!

Best Regards
Daniel