[ketse]

Hi I'm new to AIX and HMC Virtualization so any help will be appreciated.
Thanks in advanced.

What we would like to do in order to maximize High Availability is to use MPIO.

I know that the best way is to setup MPIO on the VIO Client so that if one VIO Server fails the other one will take it's place.

The question that I have is how can you set it up so that you can use
MPIO on the VIO Client.
2 VIO Servers
2 Physical disks
Each VIO Server will have a disk attached to it
Only 1 of the VIO will have be mirrored to the other disk.
That way if 1 VIO server fails the other with the mirrored disk will pick it back up and if only the disk fails it will beable to use the mirrored disk.


Thank you.

[eraserhead]

I recommend the whitepapers:

http://techsupport.services.ibm.com/...ual_client.pdf

and

http://techsupport.services.ibm.com/...OServerswp.pdf

They are very explicit about what to do. The second whitepaper also discusses SEA Failover, which you might consider as well.

Steve Stackwick

[ross.mather]

The whitepapers are good regarding redundant VIO. However you need to evaluate what Service Level you need to reach in order to decide whether tha additional management overhead of the second VIO Server is worthwhile.

In the case you are talking about here you'd need to have a machine with at least 2 SCSI adapter in it as you need to allocate a SCSI adapter to each VIO Server. Then each VIO Server needs disk space for its operating system. After that any disk room you have left on disks allocated to the VIO Server can be connected through to the LPARS. You can do this using full disks or logical volumes on the disk.

So really you need a mimimum of 2 SCSI adapters and 6 physical disks before you can implement this. In my ivory towered world I don't want to put Logical Volumes of the root disk of the VIO Servers for other Operating Systems. By perferance though I want to boot LPARS that use the Virtual I/O Server from SAN disks and not local disks. In this case VIO is at its strongest (in my not very humble opinion). The white papers only use this method.

If you do want to use SCSI volumes from each VIO you are left having to repair mirror problems frequently if you reboot a VIO (after an upgrade for instance), whereas using the same SAN disk allocated through both VIO servers that problem is not there.

What isn't discussed is the spagetti that comes from allocating your Virtual I/O slots. This is one place where you need to have a procedure in place to manage these manually. You allocate them so you need to be structured, otherwise its a mess, and virtually unmanageable. Do not be tempted to simply allocated them in numerical order.

If it helps I use: under 100 for Ethernet, 100-199 for Virtual SCSI from VIO1 and 200-299 for Virtual SCSI from VIO2. We then allocate slot 100 and slot 200 to the same LPAR - and the LPAR relate those its own slots 100 and 200.

The Ethernet slots - I always make the VLAN id equal to the slot if, ie slot 20 will always have VLAN 20 attached. It saves a lot of debugging headaches...

Someone asked me recently - if all the LPARs are booting from SAN why not the VIO itself? My answer is thatif there is a big SAN problem I can then still start the VIO and debug the SAN from there - If I cannot boot the LPAR I have nothing.

[ketse]

Thanks everyone for te help.

I relized that I now need to set up the second VIO server on a SAN because I only have one HD controller.

I assigned a FC adapter to the second VIO but I can't find the WW name so that can assign a LUN to it. Can anybody help me out with this?

Thanks.

[ross.mather]

The easiest way is to boot the whole system in full system mode and then make a note of all the WWNs then.

If you can't then allocate the new SAN card temporarily to another LPAR to find out the WWN.

If you know which port on the SAN switch the card is connected to, you'll be able to read the WWN from there as well if you just start the 2nd VIO Server into SMS mode.

HOWEVER, this will give you a much less debuggable system in the future, think what will happen with your SAN environment if you ever need to swap out a Fibre Card due to a failure, and you need to find the WWN all over again. Its worth the cost to get a 2nd SCSI adapter built in for this purpose to save money down the road at 3 in the morning :-)

[ketse]

The problem that I have though is that I can't see the Fibre cards on out SAN switch.
I tested the cable and plugged it in but still nothing shows up on that port.

Any suggestions to what I'm doing worng?

PS thanks for all your help so far.

[ross.mather]

You need to at least start the VIO Server to SMS mode and then (with any luck the fibre card will be active). If you can check the cable you can also check the link lights to see if they are active.

The quickest way to see the WWN is to allocate the card temporarily to the other VIO (via dynamic LPARING) and then read off the WWN that way. You can then remove the Fibre Card again and start up the ther VIO.

The troble is that some SAN Storage devices don't like to allocate LUNS to WWNs that it cannot see - and most SAN administrators don't like doing it either.

BTW what type of P5 are you using? It may still be easier to plug in an additional SCSI card :-)