Networked storage technology: HYPERSCSI vs ISCSI

Data Transfer Protocol iSCSI has become one of the industry's recognized Low-cost storage network solutions, but it is not the only solution, another transport protocol: HYPERSCSI can also provide Low-cost, Ethernet based SAN Solutions.

The HYPERSCSI protocol, first developed by the Singapore Data Storage Institute (DSI) in 2000, was designed to transmit SCSI data and instructions via raw Ethernet. It allows users to remotely use SCSI or SCSI based devices over the network, as conveniently as they are used locally. The DSI is a research institution jointly funded by the National Institute of Science and Technology (A*star) of Singapore and the National University of Singapore (NUS).

Unlike the HYPERSCSI protocol, the iSCSI protocol was developed under the auspices of the Internet Engineering Task Force (IETF), which uses TCP/IP to send SCSI instructions.

HYPERSCSI's supporters claim that it has a significant advantage over both Fibre Channel and iSCSI in Price, and that performance is superior to other ip-based storage solutions.

Because data blocks are sent by using raw Ethernet, the HYPERSCSI protocol completely shuts down TCP/IP protocols that lead to slow iSCSI speeds. In fact, HYPERSCSI's developers claim that its performance can be comparable to Fibre Channel, with a 21% increase in CPU utilization and 3.4 times times of Interrupt requests (IRQs: Signals sent to the CPU when a peripheral device starts or stops). They also point out that if you want to achieve the same performance as Fibre Channel, iSCSI needs to increase the CPU utilization by 33% and increase the IRQs by 6 times times.

"This is a very attractive solution," said Graham Smith, senior I/O project manager at HP's Enterprise UNIX division, commenting: "This completely solves the problem of the TCP/IP protocol." But HP has so far not planned to use the HYPERSCSI agreement on its products.

Not only that, because Hyperscsi was released last year as a source code software, it was free and protected by the GNU Public License (GPL). "You can arbitrarily change the source code without restriction," said Jesse Keating, a pogo linux HYPERSCSI Linux desktop provider.

With these advantages, you should expect the industry to be bullish on this agreement, but the fact is, many people were asked about the agreement when the answer is: "What is hyper?" ”。

For many years, manufacturers have been talking about iSCSI, and Hewlett-Packard's Smith says it is hard to anticipate the difficulty of promoting HYPERSCSI because it is primarily developed by data storage research and looks a bit like a university project. Of course, it must be admitted that many good techniques are developed through this approach.

In addition to the "Born Low", HYPERSCSI is also adversely affected by the sharing relationship, and putting SCSI on Raw Ethernet can improve performance, but there are disadvantages to abandoning TCP/IP, Smith said, without TCP/IP, there is no real error recovery mechanism, There is no guarantee that packets are sent correctly, and there is also a limit to extensibility.

Of course, there are also different views from the industry, iSCSI software provider Pyx technology company's president and CTO Andre Hedrick said: "I think it is like a motor-loaded beer cans, it can run fast, but hope that there is no obstacle, because there is no protection measures", He was sure that if iSCSI had no internal support, it would not have the heat today.

In addition, Hedrick pointed out that HYPERSCSI is not based on industry standards, which will cause stranded in a single vendor and can not extricate themselves, he also pointed out that now HYPERSCSI only on Linux applications.

Sun's CTO Balint Fleischer said: "For this protocol based on Raw Ethernet, although there are many advantages and disadvantages, but these are irrelevant, because customers do not pursue technology." For HYPERSCSI He noncommittal, said will wait to change.