By Dave Simpson and Lisa Coleman
After three years of fits and starts and false expectations, some analysts predict that 2004 will finally be The Year of iSCSI. Although end-user adoption is still miniscule, a number of both established vendors and start-ups continue to pump iSCSI products into the market.
Three of the more recent announcements came from SCSI stalwart Adaptec and relative newcomers SANRAD and Xiran.
Adaptec's iSA1500 is an external iSCSI disk array targeted at the small to mid-sized enterprise (SME) market (which Adaptec defines as companies with 20 to 1,000 employees) and applications such as storage consolidation, archival, disk-to-disk backup (the system is certified with Computer Associates' BrightStor software), remote mirroring, and replication, primarily in Microsoft Exchange and SQL Server environments.
The 1U iSA1500 comes with four hot-swappable Serial ATA disk drives, 1GB of memory, two Gigabit Ethernet ports, one 10/100 Ethernet management port, and one serial RS-232 management port. MSRP for a 1TB configuration is $10,000.
Software features available with the iSA1500 include host access control lists, automated storage provisioning, dynamic volume resizing, snapshots (with rollback), and optional local/remote mirroring. The disk array also supports the IPSec security standard, as well as RAID levels 0, 1, 10, and 5.
San Francisco-based SANRAD recently introduced its iSCSI V-Switch 2000, a dual-port iSCSI gateway for IP connectivity that targets the midrange IP storage area network (SAN) market. The 2000 allows the company to compete with other IP SAN start-ups such as EqualLogic, Intransa, LeftHand Networks, and StoneFly Networks, according to Zophar Sante, vice president of market development at SANRAD.
The switches can connect to Fibre Channel or SCSI storage systems on the back-end and to hosts on the front-end via an IP network (see diagram). The switch works with any vendor's storage subsystems, according to Sante.
SANRAD began shipping the V-Switch 2000 in January and like its high-end counterpart—the V-Switch 3000—the 2000 offers clustering, volume management, virtualization, and security features.
The 2000 interoperates with nine different iSCSI initiators and includes integrated RAID functionality. The switch also features fail-over, continual monitoring of all key components, and system configuration database preservation via removable compact Flash storage.
The switch comes with the StoragePro software suite for managing IP SANs. Pricing starts at $12,000.
Around mid-year, SANRAD plans to release a family of remote replication services for its switches.
Irvine, CA-based Xiran recently introduced the DPA-1400 iSCSI+ Accelerator, an iSCSI target and/or initiator host bus adapter (HBA). However, the DPA-1400 is being sold to OEMs primarily for iSCSI target devices.
While there are a variety of iSCSI initiator products available today—including software drivers, HBAs, and NICs—the market focus is now shifting to iSCSI targets, according to Mark Woithe, director of marketing for IP storage at Xiran.
"Most initiator products do not perform well as targets," claims Woithe. "In fact, we've seen up to a 60% performance degradation [based on internal tests conducted by Xiran]."
Xiran hopes to differentiate its board from competitors' via a relatively low price ($750—although iSCSI target pricing has not yet been established), and its DirectPath Engine technology, which the company claims enables higher performance.
DirectPath hardware performs dedicated operations traditionally handled by server operating systems for I/O-intensive operations, including iSCSI processing, according to Xiran officials.
DirectPath provides TCP termination and processes TCP/IP and iSCSI packets with low (if any) CPU utilization, according to Woithe. In target tests, Xiran claims wire-speed performance and a throughput rate of 30,000 I/Os per second per port with a CPU utilization rate of 0%. The host CPU is only used to load the firmware to the DirectPath hardware.
The 1400 provides iSCSI connectivity to existing storage devices. "We're enabling VARs, integrators, and OEMs to build low-cost iSCSI targets using existing targets and infrastructures," says Woithe.
The DPA-1400 combines a dual Gigabit Ethernet NIC, full offloading of TCP/IP and iSCSI protocol processing, and up to 256MB of buffer memory on a 133MHz PCI-X card. It supports Windows 2000/XP and Red Hat Linux 7.2 and is currently sampling to OEMs.
SANRAD's V-Switch and software provides centralized storage provisioning and traffic provisioning for quality of service (QoS) in IP SAN environments.
UNH completes iSCSI 'plugfest'
By Dave Simpson
Proponents argue that iSCSI will not be plagued by the interoperability issues that plagued Fibre Channel, largely because iSCSI is based on the ubiquitous TCP/IP and SCSI protocols. To help ensure that's the case, the University of New Hampshire InterOperability Laboratory (UNH-IOL) periodically (about every six months) holds "plugfests" to test product compliance with the iSCSI standard as well as interoperability between different vendors' products.
UNH-IOL completed the latest round of iSCSI testing last month. Participating vendors included ATTO Technology, Crossroads Systems, EMC, Empirix, Finisar, I-Tech, Intransa, iVivity, Microsoft, Network Appliance, Silverback Systems, and Xiran.
Specifically, UNH-IOL tests at three "levels": conformance with the iSCSI standard specification; interoperability with UNH-IOL's reference implementation; and vendor-to-vendor interoperability testing.
Stephen Schaeffer, UNH-IOL Consortium manager, reports that although "corner cases" of non-interoperability do crop up, "in general, iSCSI is mature and deployable. End users should not be worried about interoperability."
Schaeffer says that recent plugfests have focused on iSCSI login and security issues, which still occasionally reveal interoperability problems. The products that the lab tests consist primarily of host bus adapters (HBAs) and network interface cards (NICs), software drivers, and target devices (disk and tape subsystems).
In addition to UNH-IOL, Microsoft also does extensive testing of iSCSI products and has a certification program. However, Microsoft's tests focus primarily on compliance with its operating systems and iSCSI software drivers—not vendor-to-vendor interoperability.
"Microsoft does 'bottom-up' testing and we do 'top-down' testing," says Schaeffer. "With the Microsoft tests a vendor either succeeds or fails in interoperating with Microsoft's operating systems and drivers. Our test reference is the iSCSI standard itself, as well as product interoperability tests."
Schaeffer says that it's safe to say that iSCSI products will be more interoperable than Fibre Channel products were in the early days of storage area networks (SANs). "Unlike Fibre Channel, iSCSI is more of a 'grease layer' between TCP/IP and SCSI, both of which have been around since the earth cooled. iSCSI is a new technology, but it's based on very robust and proven technologies."
The next round of UNH-IOL tests is expected in the July time frame. For more information, visit www.iol.unh.edu.