Tech Road Map: Keep An Eye On Virtual I/O

New offerings and approaches feed multicore servers the virtual bandwidth they need.
Slot Machines
Another group of vendors, lead by NextIO with newcomers Aprius and VirtenSys, promise products that will extend the server's PCIe slots through a switch to an external I/O chassis containing additional PCIe slots. Conceptually much like the PCI SIG's Multiple Root-I/O Virtualization (MR-IOV) standard (see sidebar), but without the need for I/O cards to have MR-IOV support, these systems use a low-cost -- around $200, versus $1,500 for a converged network adapter -- stateless PCIe extender card so servers use the I/O devices drivers unmodified.

PCIe-based solutions can share any Single Root-I/O Virtualization (SR-IOV) compatible card allocating their virtual interfaces to hosts as virtual devices; cards that don't support IOV are assigned to a single host, allowing video, data acquisition, and other specialized cards to be shared across multiple hosts, albeit sequentially.

All three vendors have Serial ATA or SAS/SATA drive bays in their I/O expansion chassis. This lets them create a shared direct-attached storage pool allocating logical drives from an SR-IOV RAID controller in the chassis to hosts, which diskless servers can use for boot or other local storage at a lower cost than a boot from the SAN.

Virtual I/O may have its biggest impact in the blade server market, where a smaller number of I/O channels helps vendors increase server density. Alliances are starting to form, with IBM integrating NextIO technology in its BladeCenter HT and Dell reselling Xsigo's I/O Director.

As a temporary solution until FCoE takes over the world, a lower-cost consolidation point between servers and end-of-row FCoE switches, or a long-term solution, virtual I/O could be worth a look for the more adventurous. On the other hand, those that use new technologies without major-player support always take the risk their virtual I/O system will look like Token Ring in a year or three.

Howard Marks is chief scientist at Networks Are Our Lives, a consulting firm.

Illustration by Jupiterimages

Continue to the sidebar:
Virtualization Success Is In The Cards

Editor's Choice
Brandon Taylor, Digital Editorial Program Manager
Jessica Davis, Senior Editor
Cynthia Harvey, Freelance Journalist, InformationWeek
Terry White, Associate Chief Analyst, Omdia
John Abel, Technical Director, Google Cloud
Richard Pallardy, Freelance Writer
Cynthia Harvey, Freelance Journalist, InformationWeek
Pam Baker, Contributing Writer