disk management on Integrity VM

[Nappy_1]

i'm configuring a Service guard cluster with two nodes (physical server and an Integrity VM server)

an eva disk is presented to the two nodes. so the the disk have 4 paths

i want to attach the 4 paths to Virtual host so i added the 1st path but Integrity VM doesn't accept to add the other multiple paths
it shows the following error

# hpvmmodify -P MHRDB2 -a disk:scsi::disk:/dev/rdsk/c8t0d4
hpvmmodify: ERROR (MHRDB2): Duplicate backing device '/dev/rdsk/c4t0d4'.
hpvmmodify: ERROR (MHRDB2): Unable to add device '/dev/rdsk/c8t0d4'.
hpvmmodify: Unable to create device disk:scsi::disk:/dev/rdsk/c8t0d4.
hpvmmodify: Unable to modify the guest.


is there a way to add all 4 paths the VM host?

[sujit kumar singh]

Hi


This is better to do a Multipathing on the Host Level in IVM.

If u have some multipathing SW on the host like Secure path then u can go ahead combining the paths on both the IVM host as well as the Non-IVM Node and then present this Disk to the IVM guest on the IVM Host.


Regards

Sujit

[Nappy_1]

ufortunately i don't have a multipathing software

[Eric SAUBIGNAC]

Bonjour Nappy,

From HPVM 2.0 you can't add alternate path in a VM. In fact, HPVM is not able to transmit most of hardware SCSI evenements to the Guest. So LVM in the Guest will not be able to switch from one path to an other if one path is loosed.

So, 2 solutions : install a multipathing solution on the host. What kind of storage do you use ? Or, if you can't have such a solution (money ?) you can create a VG with alternate pathes at Host level, then present a logical volume to your guest instead of a raw device

Eric

[Nappy_1]

unfortunately the two solutions are not good because i have to configure a shared vg for a cluster between a phyical node and a virtual node.

i think that use only one path for the disk on the virtual node which will be the standby node.
this is not good but i think that there is no way

[Nappy_1]

i forgot to add that the customer don't like to pay for a multipathing software

[Eric SAUBIGNAC]

Ok, I understand.

As you have a clustered node, I suppose you have a mirror between 2 storage ?

In this case, be ware of one more thing. Due to the same limitations than for alternate path, you can't have an LVM mirror in a Guest, it is not supported. But hpvmcreate / hpvmodify will not prevent you from doing it (because they have no knowledge that disks will be tied together in the Guest). More, as long as you have no trouble with the disks in the VM, the solution LVM Mirror in the guest will seem to work. You will have problems when one disk goes bad ...

Eric

[Duncan Edmonstone]

Upgrade the VM host to 11iv3 - then you can just use the native MPIO (assuming your disk array is supported)

Your VM guest can stay at 11iv2 if required, although it does have to be the 0609 release of v2 or newer.

HTH

Duncan

[sujit kumar singh]

Hi Nappy,

Hope the following shall work.
The ideal scenario in ur case is having a Multipathing Software at the Host level in the IVM host and at the non-IVM node or to inherit the Multipathing feature that OS 11.31 provides.

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.

Mkae 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).


Regards

Sujit

[Duncan Edmonstone]

Sujit, thats not going to work - you can't take a bunch of LVs, present them to the VM guest and hope the VM fuest can reconstruct these into the original VG!

HTH

Duncan

[sujit kumar singh]

Hi Duncan,


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 im clear and correct


regards

Sujit

Regards Sujit

[sujit kumar singh]

Hi Duncan ,


the question to this answer i had myself been seeking in the post as detailed below.

If wish then i can reopen the thread.

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1299212



Regards

[sujit kumar singh]

Hi Duncan,


I have reopened that thread , can u put valuable inputs there in.


regards

Sujit

[sujit kumar singh]

Hi Nappy


Please have a look at the following thread also.


http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1299212


regards

Sujit

[Nappy_1]

hi Duncan,
i'm running Integrity VM v3.5 on hpux 11iv2

is there a way to present the 4 paths to a guest?

[Eric SAUBIGNAC · Accepted solution]

Nappy,

because you will have a cluster between a pysical node and a VM Guest, you must use raw devices at VM Guest level : data structures must be the same in both environments.

So as said Duncan, the only possible way to have multipathing to support the guest is to upgrade the VM Host, and only the VM Host, to HP-UX 11iv3 wich implement native multipathing.

Eric