MCSG/OPS in 8i on HPUX 11

[Henrique Silva_3]

Hello everyone.

I am looking to implement OPS for an application we are developing here. I do not need the Service Guard part here, only the clustering ( or shareing of the disks ). All I have been reading about OPS on HPUX, has the MCSG in front of it. I would like to know if it can be implemented on a SAN, without the MCSG part. Simply sharing the disks between the nodes in order to share the database files.

Thanks,

Henrique Silva

[cart · Accepted solution]

You still need the MC/SG at least to enable a volume group in shared mode. This feature is not available with standart HPUX.
Then OPS still rely on a cluster, that means it needs MC/SG to handle the cluster status (which nodes are up/down...)

S

[Sukant Naik]

Hi Henrique,

I tried this on my Cluster.

# cmviewcl

CLUSTER STATUS
nasva up

NODE STATUS STATE
nask1 down halted
nask2 up running
# vgchange -a y /dev/vgshare
vgchange: Activation mode requested for the volume group "/dev/vgshare" conflict
s with configured mode.
# vgchange -a e /dev/vgshare
vgchange: Cluster Services not available or unreachable on this system, for volu
me group "/dev/vgshare".
# uname -n
nask1
#

What it clearly indicates is that you need to have the MC SG running on your machine to mount your volumegroups in shared mode.

Also, when you are using OPS, you need to build packages on each node, which will activate the Shared Volume groups in shared mode and then start the oracle instance.

-Sukant

[Duncan Edmonstone]

OPS doesn't work on any platform without some sort of cluster product... OPS takes care of the things like distributed locking etc. but still needs the services of a cluster product so it can do things like
a) share virtual storage
b) know the state of all nodes
c) have HA network connections.

So OPS requires TruCluster on Tru64, VCS (or SunCluster) on Sun, HACMP on AIX, and of course, ServiceGuard on HPUX.

HTH

Duncan

[Henrique Silva_3]

Thank you guys.

I knew I needed the clustering for allowing the sharing of the volume groups. I was not sure why I needed the SG partioin of it. I guess I need it for the package the enables sharing of the volume groups.

Now, could I not simply write my own shell scripts on each server to have the sharing of the volume groups come up automatically without using the package ? What is the problem with that ? Not that I would not use SG, sicne it is already there for you, but I am trying to understand the reasoning behind it. If I can get clustering going, then, I would not need to have package control !!!

Ideas ? Thanks,

Henrique Silva

[Duncan Edmonstone]

1. If MCSG is not installed, you cannot activate a VG in shared mode... that is, you can't do a 'vgchange -a s vgXX'.

2. As I stated previously, OPS doesn't just use MCSG for disk sharing, it also uses it to obtain information on the other nodes which are running OPS (i.e. are they up and attached to the network).

3. If you try and create a 'customised' version of OPS yourself without using MCSG, don't expect to get any meaningful support out of Oracle or HP - OPS is a complex product - if it isn't configured as specified in the manuals you can expect a lot of trouble from both companies support organisations...

HTH

Duncan