vgexport vgimport on shared LUN hpux 11.31

[Mydheen]

Hi,

I am facing one issue on vgexport, vgimport regarding. Os is hpux 11.31. I have a mount point /ggate on server 86.11, and this is created using only one lun of 500gb. the mount point was working fine. later we have shared this lun with server 86.12 through storage.

means the LUN ID of this LUN is same on both the servers 86.11 & 86.12, and the disk device file will appear different.

i wanted this mount point to be activated on one server at any point of time using the shared lun. incase if i have any maintenace on server A, i need to mount this /ggate on server B. hence i followed the below procedure of vgexport, vgimport.

on first server 86.11 :

vgexport -v -p -s -m /tmp/vg_ggate.map vg_ggate

scp -p /tmp/vg_ggate.map <userid>@172.20.86.12:/tmp/

strings /etc/lvmtab (in the output of strings /etc/lvmtab, I could see /dev/vg_ggate)

then in the second server (86.12):

chown root:sys /tmp/vg_ggate.map

chmod 755 /tmp/vg_ggate.map

mkdir /dev/vg_ggate

mknod /dev/vg_ggate/group c 64 0x070000  (with same major and minor number as like 86.11 server)

vgimport -v -m /tmp/vg_ggate.map /dev/vg_ggate /dev/rdisk/disk6  (here i did not use the -s option as i am mentioning the disk name)

bash-4.3# cat /tmp/vg_ggate.map

VGID 794cba5455e98098

1 ggate

vgchange -a r /dev/vg_ggate

vgcfgbackup /dev/vg_ggate

vgchange -a y /dev/vg_ggate

mount /dev/vg_ggate/ggate   /ggate

bash-4.3# cd /ggate    (here i am checking the data available, but i could not able to see the datas)

bash-4.3# ls -lrt

total 0

drwxr-xr-x   2 root       root            96 Sep  4 14:32 lost+found

bash-4.3#

here when I checked, the datas are not present under /ggate

I hope that is enough only to use (-p –v –s –m ) option when I export from 86.11 (source server). I have not done # vgexport /dev/vg_ggate from 86.11

Now, as there is no datas available in the server 86.12 mount point /ggate,  I have unmounted in 86.12, deactivated the VG, and did # vgexport   vg_ggate.map  /dev/vg_ggate

Then tried to activate the VG on 86.11, and mounted the /ggate, but there also datas are not appearing. 

kindly seek your expert advice, as i dont have any backup for this mount point. This is a production server too. this mount point was created recently.

Regards,

mydheen

[Torsten.]

Looks like you mounted the LUN in r/w mode on both servers?

Unless you have a shareable filesystem you will destroy the data that way.

[Mydheen]

Hi Torsten,

I want to share the filesystem b/w both the servers. Active at a time on one server only. the lun is already shared between both the servers.

i believe vgexport, vgimport is the only way to achieve this.

please let me know the procedure to do this. and kindly verify whether i have followed the correct procedure or not.

note: the file system was created first, then after a month only we have shared the lun to the other server. and we tried doing this vgexport, vgimport.

regards,

mydheen

[Torsten.]

Sharing a LVM LUN and a file system is something complete different.

You shared the LVM LUN already (vgexport in preview mode, then vgimport).

Usually you activate the LUN (VG) in exclusive mode, one server at a time.

But take care, the standard file system inside the LUN is not shareable, this means if both servers have write access at the same time they will sooner or later destroy your data completely!