[alecks84]

It is my first post here so Hello everybody.

My configuration:
1 p550 (9133-55A)
2 internal disks for VIO rootvg and LPAR rootvg.

I try to have 2 VIO for failover and load balancing and dedicate one internal physical disk per VIO (RAID1 further, I have just two physical disks for the moment) .
I have just one SCSI controller [logical location: Uxxx-P1-T14], that's why the two physical disks have the same logical location "root":
disk n°1 : Uxxx-P1-T14-L3 (physical location = P2-D1) --> rootvg for VIO2
disk n°2 : Uxxx-P1-T14-L5 (physical location = P2-D2) --> rootvg for VIO1

I cannot boot the two VIO in same time.
Separate boot of each VIO is OK.
The issue is that the Uxxx-P1-T14 ressource (SCSI controller) is required for each VIO. When I boot my first VIO it is OK, but when I try to boot the second VIO, I have this error message :
HSCL03EB: allocation for Uxxx.xxx.T14 E-S slot is impossible

I hope someone have a good idea.
Thanks
alecks84

[rydekull]

If I understood what you typed correctly.

It has to do with the fact that one LPAR needs a SCSI-controller if booting from internal disk.

[alecks84]

Sorry for my english...
Each VIO server needs a SCSI-controller for booting from internal disk ?
I have 2 VIO servers and just 1 SCSI-Controller...

[mshulman1980]

It sounds like you're not giving a second VIO server a disk to boot off of.
You're probably safest at this point just using 1 VIO server. consider getting a second disk controller and another pair of disks.
Additionally, you could SAN boot the VIO servers, but I wouldn't reccomend it. You should not SAN boot just one VIO server. Their configuration must be as similar as possible if they're going to be working together.
Hope this helps.

[thomasle]

I would configure the second 4-pack hard drive backplane (feature 6593) attached to one SCSI adapter (feature 1912) via a SCSI cable (feature 4274).
I would also add two more drives so each VIO server has two drives; one for the VIO software and the second drive to be shared amongst your LPAR's. Place two drives in each 4-pack backplane. As you know, each VIO server is in its own LPAR and each needs its own SCSI controller.

[duke900ssd]

As you know, each VIO server is in its own LPAR and each needs its own SCSI controller....
With both drives on one scsi controller you will only be able to boot one VIOS at a time, as you have found.
You need another scsi controller / adapter to use the configuration you desire.

[alecks84]

Thanks for your help
So i'm going to buy a second SCSI Controller and a second 4-pack hard drive backplane...
It is a regular configuration for a p590 or p570
... but I think virtualization best practices (2 VIOS...) for p550 is too much expensive.

[cdelgadop]

Hi

This is a very common problem with configurations of p550. Looks like IBM sales specialists doesn't know that p550 servers need another backplane in order to split the internal SCSI bus so we can create at least two LPARS, so you need to buy all these HW.

Remember you can install VIOS on SAN based disk (RAID 1) provided that your p550 has at least one HBA adapter (recommended to have 2 for high availability purposes). This approach allows you to have better performance and high availability and save you some money of buying up to 4 internal disks just for VIOS mirrors.

Virtualization is not always an economic design. Let's say you want to create a SEA device to consolidate several LPAR's ethernet adapters, you need to assign at least one Ethernet adapter (commomly of two ports each) to the VIOS LPAR and config as an Etherchannel device, but, what if this only adapter go bad ??. It's probably best to buy a second one and config both adapters (that is 4 ethernet ports) as a Etherchannel device, this way you get HA and performance.

Hope this helps