topic Re: Fixing improperly split mirror in Operating System - HP-UX

Fixing improperly split mirror

Johns Manville — Sat, 16 Oct 2010 19:31:25 GMT

Working with HP-UX 11.11 on a production server.

This server had two C35txdx disk on one EVA that I mirrored with one C60txdx disk on another EVA. I believe I broke the mirror incorrectly like this:

lvreduce -m 0 /dev/vgxx/lvolx /dev/dsk/C35txdx

I believe I should have also listed the second C35 drive on the above line, thus removing both of the old drives from the mirror.

However, my situation now is NO mirror, but both the C60 and the other C35 disk are listed on the lvol currently.

I am unable to use a pvmove because this is an active mounted file system with database files. I assume pvmove would not be safe while the disks are in use. If I'm wrong, this would solve my issue.

But, if I can't use pvmove, can I simply re-mirror the lvol and break it listing both C35 drives on the command line and get to where I need to be?

I can't take this server down.

Thanks.

Re: Fixing improperly split mirror

James R. Ferguson — Sat, 16 Oct 2010 19:44:49 GMT

Hi:

A 'pvmove' is safe to do as long as you don't interrupt the process. Should you kill the process, or should something happen to cause the process to terminate, you can be left with stale logical extents.

Regards!

...JRF...

Re: Fixing improperly split mirror

Chandrahasa s — Sun, 17 Oct 2010 05:05:03 GMT

Hi,

If you could able provide below logs it will help full to have little more light on your issue.

#vgdisplay -v

#strings /etc/lvmtab

#lvdisplay -v lvname

Chandra

Re: Fixing improperly split mirror

Aneesh Mohan — Sun, 17 Oct 2010 07:43:00 GMT

Hi,

Please post lvdisplay -v /dev/vgxx/lvolx

Aneesh

Re: Fixing improperly split mirror

Johns Manville — Sun, 17 Oct 2010 13:32:22 GMT

--- Logical volumes ---
LV Name /dev/vg77/lvol1
VG Name /dev/vg77
LV Permission read/write
LV Status available/syncd
Mirror copies 0
Consistency Recovery MWC
Schedule parallel
LV Size (Mbytes) 71656
Current LE 8957
Allocated PE 8957
Stripes 0
Stripe Size (Kbytes) 0
Bad block on
Allocation strict
IO Timeout (Seconds) default
lvdisplay -v is too long, so here is part.

--- Distribution of logical volume ---
PV Name LE on PV PE on PV
/dev/dsk/c35t1d5 2559 2559
/dev/dsk/c60t2d4 6398 6398

--- Logical extents ---
LE PV1 PE1 Status 1
00000 /dev/dsk/c60t2d4 00000 current
00001 /dev/dsk/c60t2d4 00001 current
00002 /dev/dsk/c60t2d4 00002 current
00003 /dev/dsk/c60t2d4 00003 current
00004 /dev/dsk/c60t2d4 00004 current
00005 /dev/dsk/c60t2d4 00005 current
00006 /dev/dsk/c60t2d4 00006 current
00007 /dev/dsk/c60t2d4 00007 current

Re: Fixing improperly split mirror

Johns Manville — Sun, 17 Oct 2010 13:35:52 GMT

Here is the /etc/lvmtab:

/dev/vg00
/dev/dsk/c1t2d0
/dev/dsk/c2t2d0
/dev/vg15
/dev/dsk/c35t0d0
/dev/dsk/c60t0d4
/dev/vg16
/dev/dsk/c35t2d6
/dev/dsk/c35t0d4
/dev/dsk/c35t0d5
/dev/dsk/c60t0d5
/dev/dsk/c60t1d0
/dev/dsk/c60t1d2
/dev/dsk/c60t1d3
/dev/vg17
/dev/dsk/c35t0d2
/dev/dsk/c60t0d6
/dev/vg18
/dev/dsk/c35t0d3
/dev/dsk/c60t0d7
/dev/vg35
/dev/dsk/c35t2d4
/dev/dsk/c60t1d5
/dev/vg38
/dev/dsk/c35t2d7
/dev/dsk/c60t1d1
/dev/vg39
/dev/dsk/c35t3d0
/dev/dsk/c60t3d0
/dev/vg48
/dev/dsk/c35t4d1
/dev/dsk/c60t3d1
/dev/vg01
/dev/dsk/c1t0d0
/dev/dsk/c2t0d0
/dev/vg03
(AT1
/dev/dsk/c60t0d1
/dev/vg49
/dev/dsk/c35t5d5
/dev/dsk/c60t1d4
/dev/vg_app
/dev/dsk/c60t2d7
/dev/vg70
/dev/dsk/c60t3d2
/dev/dsk/c60t3d3
/dev/vg71
/dev/dsk/c35t5d2
/dev/dsk/c35t0d7
/dev/dsk/c60t1d6
/dev/vg72
/dev/dsk/c35t5d6
/dev/dsk/c35t1d0
/dev/dsk/c60t1d7
/dev/vg73
/dev/dsk/c35t5d7
/dev/dsk/c35t1d1
/dev/dsk/c60t2d0
/dev/vg74
/dev/dsk/c35t6d0
/dev/dsk/c35t1d2
/dev/dsk/c60t2d1
/dev/vg75
/dev/dsk/c35t6d1
/dev/dsk/c35t1d3
/dev/dsk/c60t2d2
/dev/vg76
/dev/dsk/c35t6d4
/dev/dsk/c35t1d4
/dev/dsk/c60t2d3
/dev/vg77
/dev/dsk/c35t6d5
/dev/dsk/c35t1d5
/dev/dsk/c60t2d4
/dev/vg78
/dev/dsk/c35t6d6
/dev/dsk/c35t1d6
/dev/dsk/c60t2d5
/dev/vg79
/dev/dsk/c60t2d6
/dev/vg14
/dev/dsk/c35t2d0
/dev/dsk/c60t0d3
/dev/vg02
/dev/dsk/c60t0d2
/dev/vg04
/dev/dsk/c35t2d2
/dev/dsk/c60t0d0

Re: Fixing improperly split mirror

Johns Manville — Sun, 17 Oct 2010 13:38:15 GMT

Here is the vgdisplay -v:

--- Volume groups ---
VG Name /dev/vg77
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 1
Open LV 1
Max PV 32
Cur PV 3
Act PV 3
Max PE per PV 13000
VGDA 6
PE Size (Mbytes) 8
Total PE 18555
Alloc PE 8957
Free PE 9598
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vg77/lvol1
LV Status available/syncd
LV Size (Mbytes) 71656
Current LE 8957
Allocated PE 8957
Used PV 2

--- Physical volumes ---
PV Name /dev/dsk/c35t6d5
PV Status available
Total PE 6398
Free PE 6398
Autoswitch On
Proactive Polling On

PV Name /dev/dsk/c35t1d5
PV Status available
Total PE 2559
Free PE 0
Autoswitch On
Proactive Polling On

PV Name /dev/dsk/c60t2d4
PV Status available
Total PE 9598
Free PE 3200
Autoswitch On
Proactive Polling On

Re: Fixing improperly split mirror

Johns Manville — Sun, 17 Oct 2010 13:41:44 GMT

Unless someone has something else to say about pvmove, it looks like that is the fastest way to resolve this issue. My concern is data corruption. I thought pvmove might cause corruption if the disk I am moving was being written to.

Thanks all.

Re: Fixing improperly split mirror

Bala C — Mon, 18 Oct 2010 01:01:07 GMT

John,

lvreduce -m 0 /dev/vgxx/lvolxx

This will definitely remove the mirror. What I understand from your output is that you have removed the mirror.

What I would suggest you to do is this:-

lvreduce -m 0 /dev/vgxx/lvolxx -> To confirm if any other mirror exists.
lvextedn -m 1 /dev/vgxx/lvolxx /dev/dsk/cxxtxdx /dev/dsk/cxxtxdx.

This is much simpler and better way to overcome the situation rather than the pvmove stuff.