[edcrosbys]

Is there a way to configure a p550 so that you can create two VIO Servers both accessing different halfs of one tray? If so, does anyone have the part number(s)?

Thank you!

[cdelgadop]

Hi

Yes, you can. You need to have two different SCSI backplanes in the front side of your p550. This way you can have two 4-pack disks and assign each to diferent LPARs, each of that will be a VIOS. You will need at least one PCI-X free slot to install tha SCSI adapter needed to connect to the second internal SCSI backplane (6593). More info please take a read of the following redbook:

http://www.redbooks.ibm.com/redpapers/pdfs/redp9113.pdf

Hope this helps

[ross.mather]

Alternatively use a D20 I/O drawer if you need the original 8 disks for you VIO configuration.

In the end a VIO Server is just an LPAR and its the relationship between an adapter (in this case the SCSI Card) and the LPAR its allocated to that determines where this disks will be seen.

[edcrosbys]

Thank you Very Much!!!

[jrigler]

Another possibility is to SAN boot each vio server, then you wouldn't need scsi. We are actually going to one of these 550Qs soon and will be trying out the D20 solution since we have one laying around.

[Koetje]

We got it running that way.

What we did was have 2 scsi controllers and 2 backplanes.
4 disks / backplane (and so 4 disks / controller)

No raid or anything fancy.

2 Fibercards to a SAN.

We installed 2 vio servers each with 1 scsi controller and 1 fiber card.

Then we had 3 disks / vioserver in a clientvg and made a logical volume / disk as the rootvg of the client LPAR's
Cause you do it in mirror and mirror later the Rootvg on the LPAR you have really good performance (dedicated disk / rootvg)
The data for the server is al put on LUN's on the san with MPIO support.

The performance is really great as the different parts can all IO without having to wait for eachother.

[ross.mather]

The trouble when you do host based mirroring from the separate VIO servers is that you always have to resync your root volume group after you reboot your Virtual I/O server.

In this case where you are using MPIO and have a fibre conbnection to the SAN you are much better off if you use a separate SAN LUN for the rootvg of each LPAR. When its connected via both VIO servers (like the data LUNS) then you get the optimum setup.

And I'd back that configuration against anything using the Logical Volume Manager at VIO level.