query on shared mode in cluster env

[himacs]

Hi Admins,

I need some clarifications on shared mode.

1.To activate a VG in shared mode,we need to execute vgachange -S y first..?
2.On what circumstances we have to activate VG as shared ?

I think only with active-active cluster.So that both the system will be having read-write access on VG.


Regards
himacs

[melvyn burnard]

You need to be careful with your wording here.
There is LVM Exclusive mode (vgchange -c y and then vgchange -a e) for Serviceguard,
and then there is LVm Shared mode (also known as SLVM) which is enabled when you install SGeRAC.
This allows you to set the mode to S, as in vgchange -a S, and this allows the VG to be activated in Shared mode, in other wiords in read/write mode on multiple nodes.

[shanmuhanandam]

Hi,

yes, you need to run the "vgchange -S y" for activating the vg in shared mode.
But if you have installed Service guard ext for RAC, then only you can activate the Vg's in shared mode.

Regds,
Shan,