Previous blog entries have described scalability improvements that improve virtual disk and network I/O performance.
This new update adds scalability in a different context, by increasing the number of virtual I/O devices a domain can have.
Every virtual I/O device requires a Logical Domain Channel (LDC) endpoint.
Previous product versions had a limit of 768 LDCs (or 512 on UltraSPARC T2 systems) per domain (not per system) that constrained growth.
This set a maximum number of virtual I/O devices in a domain, which impeded migration of large configurations that might have
hundreds of disk devices or network connections. While this could be addressed in a number of ways, such as using physical I/O or consolidating many
small LUNs onto fewer large LUNs, it was an impediment to adopting Oracle VM Server for SPARC.
It especially affected how service domains could be used, since each service domain has LDC endpoints for each of the virtual devices it provides to guests.
With this new update, and with associated system firmware levels, LDC endpoints are arranged into a large pool which can be shared among domains.
As described in Using Logical Domain Channels, each domain
can have 1,984 LDC endpoints on SPARC T4, SPARC T5, M5, and M6 systems, out of a pool of 98,304 LDC endpoints in total.
The required system firmware to support the LDC endpoint pool is 8.5.1.b for SPARC T4 and 9.2.1.b for SPARC T5, SPARC M5, and SPARC M6.
This more than doubles the number of I/O devices available to a guest domain, and can be implemented by installing the current firmware
and moving to the Oracle VM Server for SPARC update.