Fibre Channel remains the technology of choice for most virtual server environments even as iSCSI storage-area networks (SANs) gain traction. Read this SearchStorage.com Special Report to learn how some storage professionals are evaluating 10 Gigabit Ethernet (10 GbE) iSCSI SANs as they expand their virtual server environments
Table of contents
iSCSI vs. Fibre Channel for virtual server environments
SAN and server virtualization management podcast
Channel view: Storage resources in a server virtualization environment
10 GigE bodes well for iSCSI
Virtualization and the NPIV factor
When IT departments began virtualizing servers, many followed the path of least resistance with storage. Small companies initially opted for direct-attached storage (DAS) as they weighed the merits of shared storage. Midsized to larger organizations often turned to their existing Fibre Channel (FC) arrays.
The Apartment Investment and Management Company (AIMCO) in Denver was no different. The real estate investment trust's foray into server virtualization consisted of a two-processor license of VMware Inc. ESX Server with DAS plus its existing Fibre Channel SAN. When AIMCO added eight ESX servers last year, it stuck with its FC Hewlett-Packard (HP) Co. StorageWorks 6100 Enterprise Virtual Array (EVA).
But Chris Bell, a systems administrator in AIMCO's Greenville, S.C., data center, is now intrigued with10 Gigabit Ethernet (10 GbE) and iSCSI SANs, as AIMCO considers a possible expansion of its virtual server environment. He expressed particular interest in NetApp's storage virtualization and multiprotocol storage devices that support iSCSI out of the box as opposed to the EVA 6100, which AIMCO hasn't licensed for iSCSI.
→ Editor's Tip: Read this article to learn more about the latest survey results on Fibre Channel and iSCSI use.
Jeff Boles, senior analyst and director, validation services at Taneja Group in Hopkinton, Mass., talks about the pros and cons of Fibre Channel and iSCSI SANs in virtualized environments in this SearchStorage.com FAQ and podcast.
Find out which type of storage architectures and storage virtualization products are most common among companies with virtual server environments.
→ Editor's Tip: To listen to this SearchStorage.com Special Report podcast click here.
Server virtualization in general, and VMware in particular, is supposed to help your customers save money by increasing the utilization of physical server hardware. For the most part, it works. Tales of successful ROI server virtualization projects are commonplace. In the project's wake, however, is a storage disaster area that your customers need help resolving.
The solution is a relatively simple one -- a tool to better manage a customer's storage I/O bandwidth combined with higher utilization rates. But you need to know how to use the tool and at what frequency.
→ Editor's Tip: Read this article to learn more about managing server virtualization environments.
The advent of 10 Gbps Ethernet (10 GbE) bodes well for iSCSI. With Dynamic TCP Offload technology added to 10 Gbps adapters running iSCSI, users will see the benefits -- higher performance and access -- of removing TCP processing from the host computer and placing it on a dedicated host bus adapter (HBA) from vendors such as Alacritech Inc., Neterion Inc. and NetXen Inc. Dynamic TCP Offload takes advantage of Microsoft Corp.'s TCP Chimney Offload technology that offloads the TCP stack to the network card.
According to the Stamford, Conn.-based market research group Gartner Inc., iSCSI is expected to be a $2 billion market by 2010. In addition, Framingham, Mass.-based IDC estimates that from now through 2010, iSCSI SANs will show a compound annual growth rate of 74.8% for worldwide revenue vs. 4.1% for Fibre Channel. IDC also claims the iSCSI protocol will capture more than 10% of storage systems revenue and an even greater percentage of capacity by 2008.
→ Editor's Tip: Read this article to learn more about the 10 GbE factor.
N_Port ID Virtualization (NPIV) tackles the problem of how multiple virtual servers access the Fibre Channel SAN. Usually, the SAN wants one port ID -- which is used as the basis for masking and zoning -- for each server. However, "virtual servers share the physical HBA and get a virtual port ID," said Clodoaldo Barrera, distinguished engineer and chief technical strategist for IBM Corp.'s System Storage Group. NPIV defines how multiple virtual servers can share a single physical port ID.
→ Editor's Tip: Read this article to learn more about the NPIV factor.