Service guard

[Jilan]

I am new to the Service Guard, I am getting confuse about what is lock disk?
1. what is sharable VG
2. exclusive VG
and how do we determine the IP's for packages, HB and Lan...

Please help me. Thanks.

[melvyn burnard]

For the Lock Disc, read:
http://docs.hp.com/en/B3936-90070/B3936-90070.pdf
To get an understanding of Serviceguard,read the Managing Serviceguard manual at:
http://docs.hp.com/en/ha/#Serviceguard

Consider booking on to a Customer Education course for Serviceguard

[Eric SAUBIGNAC]

Hi Jilan,

though Melvyn is quite right with taking a course, here are some answers :

- sharable VG is simply a VG that is known by every node in the cluster that needs it. You create the VG on one node and import it on others. That's mean that you have a storage system shared between nodes.

- exclusive VG. Though a VG is sharable, in most cases you don't want to activate it at the same time on different nodes : LVM and standard vxfs filesystems don't know how to deal simultaneously with a common object on different nodes. So you have to put the VG in exclusive mode so that just one node at the same time is able to activate it.

exclusive mode is a behavior of Serviceguard : no SG, no exclusive mode.

The proper way to change mode is :

vgchange -a n vgXXX --> deactivate VG
vgchange -c y vgXXX --> put it under control of SG

Now, you can activate your VG, but not with the traditional "-a y" option :
vgchange -a e vgXXX --> activate the VG in exclusive mode

From this point you will not be able to activate the VG on another node with "-a y", nor "-a e" (note : you can still activate it in read-only with "-a r"). You will have to first deactivate the VG on the first node to be able to activate it with "-a e" on another one.

Now, if you want to go back to normal behavior, you will have to :

vgchange -a n vgXXX --> deactivate VG
vgchange -c n vgXXX --> no more control with SG

Then you can activate your VG with "-a y".

"and how do we determine the IP's for packages, HB and Lan..."
Well, really it depends on so many paramaters that there is no cooked guide. Some rules may be :

- always at least 2 separate lan or vLan, with different subnet, one dedicated for HB, and if not possible, HB on each ethernet connection.
- IP for packages are in the same subnet than host's IP

Hope this whill help

Regards
Eric

[Jilan]

Thanks to all...:-)