Virtual SCSI adapters

Virtual SCSI (Small Computer Systems Interface) adapters on IBM^® eServer™ i5 systems with Linux^® logical partitions provide one partition with the ability to use storage I/O (disk, CD, and tape) that is owned by another partition.

A Virtual SCSI client adapter in one logical partition can communicate with a Virtual SCSI server adapter in another partition. The Virtual SCSI client adapter allows a logical partition to access a storage device being made available by the other logical partition. The partition owning the hardware is the server partition, and the partition that uses the virtualized hardware is the client partition. With this arrangement, the system can have many server partitions.

A server with two partitions: an i5/OS partition with a Virtual SCSI server adapter, and a Linux partition with a Virtual SCSI client adapter.

For example, partition A provides disk space to partitions B, C, and D. A partition can simultaneously use virtual I/O from more than one partition. Therefore, using the example, while partition A provides disk space to partitions B, C, and D, partitions A and B can use a tape drive connected to partition D. In this case, A is serving D for disk space, while D is serving A for the tape device.

Single server,two partitions:i5/OS partition,virtual disk space,Linux partition.

Disk unit, CD/DVD, and tape on an IBM eServer i5 system are based on the SCSI protocol using the ANSI SCSI Remote DMA (Direct Memory Access) protocol. Therefore, Linux partitions can access data among each other or by an adapter that is directly attached to the memory of other partitions.

The virtual SCSI client device driver is not capable of storage protection using Redundant Arrays of Independent Disks (RAID). While the Linux operating system allows software RAID protection of virtual disks, the recommended technique for protecting disk storage is to configure the virtual I/O storage server to perform the disk protection.

Note: Virtual SCSI server adapters can only be created in partitions of type i5/OS^® and Virtual I/O Server.

Here are the steps to create Virtual SCSI adapters:

From the HMC , choose VSCSI setup for Linux (Client)
Right click on Profile and select Properties.
Click Virtual I/O.
Select SCSI radio button, then
click Create button.
Enter slot number and adapter type as Client.
Enter remote partition (i5/OS) number and remote partition slot number (i5/OS)