pseudo exclusive vg activation

[Paul Barmettler]

Is there anybody who knows about a "pseudo exclusive vg activation", that means activating a volume group in a shared environment (three nodes on one FC30) without MC/SG, making shure that the same vg cannot be activated from another node.

[Rainer von Bongartz]

As far as I know this is not possible as the manual page for vgchange states:

WARNINGS
Ordinary Operation
In ordinary operation (i.e., without the optional high availability software), it is possible to activate a volume group for read-write access from more than one physically connected system, leading to a high potential for data corruption.

[melvyn burnard]

NO. this is not available without ServiceGuard.
I do believe that the VxVM available on HP-UX 11i will allow this, but do not know VxVM enough.

[Satish Y]

Hi paul,

Deactivate volume group
# vgchange -a n /dev/vg03

Enable volume group for HA cluster
# vgchange -c y /dev/vg03

Enable volume group for HA cluster and mark as sharable
# vgchange -c y -S y /dev/vg03

Activate volume group in exclusive mode
# vgchange -a e /dev/vg03

Activate volume group in shared mode
# vgchange -a s /dev/vg03

If u r not using HA cluster u can skip step2 and option "-c y" in step3.
However by default it will not get activated from other node until u do vgexport and vgimport.

Hope it is clear.

Cheers...
satish.

[John Palmer]

Not possible without MC/Serviceguard.

However, depending on what you are trying to achieve, you could remsh a script on the other boxes to check if the VG is activated elsewhere (run vgdisplay maybe) or you could only configure the VG (ie vgimport it) on one particular server.

[Bill McNAMARA_1]

Not without service guard.
VxVM does offer some clustering support, but it's a licenced extra I believe and in any case, it is integrated into mcsg rather that replacing it.

Bill

[Satish Y]

Sorry Paul, I didn't see the phrase "... without MC/SG ...." in ur question. It is not possible without MC/SG. What Rainer told is correct.

Cheers...
satish.

[Peggy Fong]

Actually we did this - but in a manual sort of environment where we would control which system would have the volume group manually.

We had a separate file that was similar to /etc/fstab that contained the file systems in the "shared vgs". We had scripts that would be run manually to either export or import the vg and a script to activated and mount the file systems on the server we wanted them on. We did not leave the VGs available on each server(used vgimport/vgexport) so we had to script the process of creating the directories and group files before doing the imports and also had to manage the map files....

MC/SG handles this much better (especially with lock disks to prevent data corruption), but it is possible to create a psuedo environment, just not normally recommended.

Hope this helps.
Peggy

[Bill McNAMARA_1]

Well I suppose you can script in a vgexport and vgimport once you configure in /etc/lvmrc
not to activate all vgs automatically on bootup.

http://forums.itrc.hp.com/cm/QuestionAnswer/1,1150,0x237c37f45ef7d4118fef0090279cd0f9,00.html

Later,
Bill