AIX

No, your RAID controller is only connected to your DVD drive. If it does go bad, just your DVD drive won't work. Your disks should remain unaffected. Assuming your LPARs are multipathed and have network connections going through each VIO server, if one of your SAS Adapters does go bad, the VIO server using it will go down till the parts are replaced, but since you have dual VIO servers, your LPARs should move their connections through the other VIO server that is still running and be fine. They'll throw a lot of errors in the errpt, but should continue to run.

Another question, I got the installation of the dual vios working and

I am trying to understand how the extenal connectivity from the VIO Client LPAR works in a VIOS environment.

I will appreciate if someone can explain this.

Below is how interfaces are setup in the VIOS server

VIOS 1 --- similar setup is for VIOS 2

ent0, ent2 __ etherchannel ( ent6 ) --- ent4 (Virtual) --- ent7 (SEA)
----ent5 (Ctrl chan)

ent1 -- Has a I/P address bound

Now, If a client LPAR needs to send packets to a external address, how are the packets routed to the extenal network.

Will the packets go from Client LPAR (Virtual Ethernet) --->vios ENT7 - ENT4 - ENT1.

This is the best explanation I can give you. Consider a situation where you have a VLAN (100 for this example) then this VLAN will exist as physical and virtual (in the Hypervisor). Your example above would result in ent0 and ent2 would be connected to the physical VLAN and by virtue of the etherchannel construction ent6 is also connected.

The command:

Code:

mkvdev -sea ent6 -vadapter ent4 -default ent4 -defaultid 100 -attr ha_mode=auto ctl_chan=ent5

the -defaultid 100 flag sets the VLAN id to 100 for this virtual adapter.

would result in the ent7 adapter being created. This is the virtual adapter which would carry the virtual VLAN address for LPAR communication through the VIO servers. Both VIO servers would have the same characteristics set so there would be identical Ethernet adpaters on both VIOS but the trunk priority would be set to alternate values (1, 2 etc).

When creating the Ethernet adapter on the client LPAR one selects the VLAN 100 on the drop down menu on the HMC on both VIO servers. As the adapters on the VIO server have been configured to talk on VLAN 100 nothing else needs to be done except allocating an IP address when the LPAR is powered on. No IP address needs to be added to the VIO virtual ethernet adapter.

All traffic to the outside world from the client LPAR would be as follows:

Client LPAR Ethernet adpater ent0 > along the Hypervisor VLAN 100 > into the VIO server SEA ent7 > Upto the virtual adapter ent4 > through the etherchannel adapter ent6 > finally out of ent0 and ent2 to the real network infrastructure.

This unfortunately is the hardest part of VIO construction to get your head around!

well.. as I remember traffic from Lpar takes this route to external network

Code:

Lpar traffic ----> VIOS ent4(Virtual_adapter)  ----> ent7(SEA) ---> ent6(Etherchannel)

Yes this is the common misconception. Have a look at the MKVDEV command. The virtual adapter ent4 was created using the menu from the HMC or if you are really adventurous keyboard commands on the HMC. I have seen both examples where the mid point adapter is classed as the SEA and the end adapter which connects to the Hypervisor VLAN as the virtual. However for the sake of clarity I feel the opposite is better as the virtual is created on the HMC for each VIO and the MKVDEV command connects the virtual to the each SEA adapter. Very confusing!

Thanks JohnF. I understand that SEA is a Layer 2 bridge between the physical and the virtual interface. But in this case , only ent1 has a I/P. So, without the I/p how is the trafiic send from ent0 or ent2 ?

Code:

ent0, ent2 __ etherchannel ( ent6 ) --- ent4 (Virtual) --- ent7 (SEA) 
----ent5 (Ctrl chan) 
 
ent1 -- Has a I/P address bound

Attached is a diagram of how I have the VIO networks layed out. IBM use to say to NOT put the VIO IP on the SEA, but I think they changed and now they are saying to put it on the SEA. I think I like it better on its own etherchannel with one virtual adapter connected to the two different internal VLANs. Hopefully the picture will make it a lot more clear. The "ent0" on both VIO servers is the physical adapter. "EC" is "EtherChannel".

Essentially, the VIO server's IP on the etherchannel ends up being configured just like all the LPARs... with one virtual adapter connected to each VLAN.