SG Cluster using the IVM Guest as nodes on different hosts

[sujit kumar singh]

my requirement is :

To form a MCSG clustering using 2 IVM guests guest1 and guest2 that are on two different nodes, host1 and host2 respectively.

I am not allowed to run the HP IVM Guest as SG package.

The hosts are running 11.23, are connected to EVA 4K storage, Guets shall also run 11.23.

I do not have any Dynamic Multipathing solution like Securepath at the Host level.

Can i create a VG on the host1, Map the VG on to host2, assign the LVs from that VG to the guest1 and guest2 and create a SG cluster between guest1 and guest2.

I want the LVM on the hosts top help me and do not want to do a SG Clustering at the host level.

This is very urgent. Is this possible in the above limitations that i have stated? If yes , please suggest.

can i usse vgchange -S y VG_name and vgchange -a s for the base VG that i will create on the host say host1?

This is for the IVM Version 3.50 and hp-ux 11.23 is Mar 2008

[Steven E. Protter]

Shalom,

Few thoughts.

You should try your vgchange command in a test environment.

For a volume group to be shared by SG, it needs to be accessible by all nodes. This means it needs to be on the EVA, not local disk for one of the nodes.

I think that means the answer to your question is no.

SEP

[Emil Velez]

You can have Virtual machines as ServiceGuard nodes especially if they are on different physical nodes.

If your package needs a VG you should make sure those are real luns that pass through the VM hosts to the VM Guests.

see the link
http://docs.hp.com/en/T2767-90105/apas06.html

Shows that VMs can be SG nodes and it is supported.

[sujit kumar singh]

Yes that is true the Release notes say that it can be done.
So i am trying to do the SG Clustering between the two VM Guests guest1 and guest2 that are respectively on host1 and host 2.

And as also suggested by you that the EVA4K LUN that is visible to both the hosts has to be presented to the corresponding guests on the hosts as Disks and not as an LV?

Then i will not be able take advantage of the PVlinks as the hosts do not have Securepath in them.

So can i make a VG on the hosts with the EVA 4K LUN(adding the PV LInks) and create an LV and assign the LV to the IVM Guets?
That only i was looking out for. Hope i am clear.

Also when i create such a VG on the host which at the host level does not have MCSG, I want to achieve the same with the vgchage -S y and vgchange -a s for the VG on both the hosts?

IN this hypothetical situation ,with the cluster running and say pkg is running on guest1 that is on host1, what shall happen if the packcage is made to switch over to guest2 which is on host2.

Remember that the Shared VG still remains activated on host1 ??????

[sujit kumar singh]

i request u all to reply this question please as this is an urgent requirement with the customer .


Can anyone help please over this ?/

[sujit kumar singh]

Hello,



I have not 11.31 nor Securepath or any multipathing Software. In that case is the following way of configuring an MCSG cluster with one node as a Full server and the other as an IVM guest possible?

If u dont have Either, u r left to use the alternate PV link feature of the LVM at the Host Level of the IVM host, create LVs and assign the same to the IVM Guest.

This i think shall require as follows:


Suppose u have the Disk path appearing at the both the Servers at the host level as : /dev/rdsk/c8t0d4 dev/rdsk/c4t0d4 dev/rdsk/c10t0d4 and dev/rdsk/c12t0d4 say


On the non-IVM Host do the following:
#mkdir /dev/vg02
#mknod /dev/vg02/group c 64 0x020000
#vgcreate /dev/vg02 /dev/rdsk/c8t0d4 dev/rdsk/c4t0d4 dev/rdsk/c10t0d4 dev/rdsk/c12t0d4
This creates the VG and integrates the Paths as Alternate paths in the VG vg02.
create LVs lvol1 lvol2 etc on that.
#vgexport -p -v -s -m /tmp/vg02.map

rcp this map file on to the IVM host at /tmp/vg02.map and import the VG over there.
on the IVM Host:
#mkdir /dev/vg02
#mknod /dev/vg02/group c 64 0x020000
#vgimport -v -s -m /tmp/vg02.map /dev/vg02
so the IVM host shall get these LV of the VG.


Assign the LVs to the IVM guest (not the Disks!!!)
#hpvmvodify -P -a disk:scsi::/lv:/devvg02/rlvol1 etc...

Once u have ssigned these LVs (Not the disks!!!) to the IVM guest and u can see them as disks in the IVM Guest ioscan go to the rest part as creating the VG for the Cluster on the IVM Guest.

ON the IVM guest:
rcp the map file from the non-IVM host and put that into /tmp/vg02.map

then,

#mkdir /dev/vg02
#mknod /dev/vg02/group c 64 0x020000
#vgimport -v -s -m /tmp/vg02.map /dev/vg02


Once imported take VG CFG backup
#vgcfgbackup /dev/vg02

Now deactivate the VG on the non-IVM host as well as the IVM host and try activating the VG on the IVM Guest.

Make sure that non-IVM host as well as the IVM guest have MCSG Installed on them.

Try following the remaining Process for Cluster creation.

Here the LVM Alternate path and assigning of LVs to the IVM Guests helps u get the advantage of Alternate Pathing ( Remember that this is not Multipathing).








Might be i also was not too sure, But what if VG vg02 has only one LV say lvol1 in the above description!!!!


And then Assigning the space as reqd for the package by creation of Single LV-ed VGs on the Host and assigning those LVs to the Guest and using them as separate VG s in the configured package .

An SG package would have handled those as different VG s configured in the packcage.


Hope I m clear and correct





Regards

[Duncan Edmonstone · Accepted solution]

sujit,

no you can't do this - see the following 

http://docs.hp.com/en/10560/IntegrityVM_HA_Solutions-SGandVM.pdf

Sepecifically see p13 - Storage considerations.

HTH

Duncan

[sujit kumar singh]

Thanks Duncan for the Suggestion as conveyed


Regards

Sujit

[sujit kumar singh]

thanks for the valuable knowledge sharing....
Regards
Sujit