This information discusses how I/O pools must be used to switch I/O adapters (IOAs) between i5/OS® logical partitions that support switchable independent auxiliary storage pools (IASPs).
An I/O pool is a group of I/O adapters that form an IASP. Other names for IASPs include I/O failover pool and switchable independent disk pool. The IASP can be switched from a failed server to a backup server within the same cluster without the active intervention of the HMC. The I/O adapters within the IASP can be used by only one logical partition at a time, but any of the other logical partitions in the group can take over and use the I/O adapters within the IASP. The current owning partition must power off the adapters before another partition can take ownership.
IASPs are not suitable for sharing I/O devices between different logical partitions. If you want to share an I/O device between different logical partitions, use the HMC to move the I/O device dynamically between the logical partitions.