VIO SCSI ID

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Configuration of the virtual I/O adapters requires the knowledge of disk layouts as well as networking configuration. The virtual SCSI adapters require server and client side adapters to be configured on the HMC. The server side portion of the SCSI adapter, configured on the VIO, requires a frame wide unique "slot number" be defined. For high availability a server side portion of the SCSI adapter must be configured for each VIO server. This means that each virtual disk or logical volume connection is associated with two server side SCSI adapters, one on each VIO server. By convention the standard has become that each SCSI adapter is numbered as a multiple of 10, with the first SCSI adapter of the server side high availability pair being configured on the first VIO server and ending with the number 0, i.e., 210, 220, 230, 240, ... The second SCSI adapter of the server side high availability pair is configured on the second VIO server and ends with the number 5, i.e., 215, 225, 235, 245, ...

For each LPAR that uses virtual disk or logical volumes, a client side virtual SCSI adapter must be configured on the HMC. The client side of the virtual SCSI adapter requires additional information and it's settings to correspond with the server side of the SCSI adapter. Coordination of the slot numbers defined here will make debugging and tracking of problems much easier and is highly desired. The information required to configure a client side SCSI adapter includes slot number, the name of the server side SCSI adapter remote partition, and the slot number of the server side SCSI adapter on the remote partition. The client side slot number should correspond with the server side slot number to make debugging and tracking easier. As an example of defining both server and client side SCSI adapters in a high availability environment:

For each LPAR, a pair of virtual SCSI adapters shall be configured to be used for attachment of the operating system and paging disks. Another pair of virtual SCSI adapters shall be configured for the purpose of application disk attachment. The virtual SCSI adapters designated for use as operating system disk attachment shall be numbered between 10 and 199. The virtual SCSI adapters designated for use as application disk attachment shall be numbered between 200 and 499.

Using this standard, each VIO server will have one virtual SCSI adapter per LPAR for the operating system, and one virtual SCSI adapter per LPAR for the application storage. Each LPAR will reference two virtual SCSI adapters, one from each VIO server, for the operating system storage, and two virtual SCSI adapters, one from each VIO server, for the application storage. Examples of this is shown below.

Example Virtual SCSI Slot Numbers

LPAR	VIO 0 OS Slot	VIO 1 OS Slot	VIO 0 Appl Slot	VIO 1 Appl Slot
daladcal01	10	15	200	205
daladfim03	20	25	210	215
daladesp01	30	35	220	225
dalapega01	40	45	230	235
dalaaora02	50	55	240	245

Each virtual SCSI adapter may have one or more disks with it, depending upon the LPAR requirements. These disk associations are performed on the VIO server by referencing the slot numbers assigned to each LPAR.

This virtual SCSI adapter information can be automatically gathered from an existing frame through the HMC using the script "virtualscsi.ksh. Example output from this script follows: