Internet SCSI (iSCSI)-based storage will outpace all existing storage types over the next five years, but early adopters are unlikely to use it as a replacement for Fibre Channel storage area networks.
That's according to Graham Penn, associate VP for storage for IDC Asia Pacific, who says iSCSI customers are primarily adopting it for its cost, ease of installation and as a platform to run less business-critical applications or run it in testing and development environments.
SANs typically require a dedicated infrastructure to interconnect hosts and storage systems. The primary means for these interconnections are Fibre Channel (FC) networks that provide the SCSI transport. The result is that separate parallel networks must be built to support applications and storage. Also, FC requires special hardware and handling, since it can't be transported in its native form over WANs due to distance limitations.
iSCSI, by contrast, is compatible with existing IP LAN and WAN infrastructures, and more cost-effective. A 2005 Merrill Lynch/McKinsey study showed that the total software/hardware cost of an IP SAN storing 2 terabytes of data is $77,000; a Fibre Channel SAN of the same size would cost more than $180,500.
That said, users will find enabling iSCSI remains a challenge, says Penn, thanks to the lack of a uniform and standard way of providing it. 'There's no standard configuration for users to refer to with each vendor having different solutions,' he says, which is also a factor for the limited rate of deployment thus far, especially in large corporate datacenters. 'Most corporate data centers using FC have continued to use it.'
Li Qing Qiao, product marketing manager for HP's StorageWorks division, says that iSCSI is typically widely used in environments where the cost of the technology is the number one priority. 'We do see the emerging market of iSCSI being in remote branch data centers, storage consolidation, and in direct-attached storage to SAN migration.'
According to Ian Loh, director of emerging solutions at EMC South Asia, enterprises will have a case for deploying a mix of IP and FC SANs to match price and performance to SLAs as part of an information lifecycle management approach for maximum cost efficiencies. Loh believes there is real merit in iSCSI enabling low-cost IP SANs, especially for first-time SAN users and organizations that want to network more of their servers and second-tier storage.
'But EMC believes that FC will continue to be the preferred SAN protocol, especially for large enterprise-level storage deployments that require high availability, application performance and security,' added Loh.
All experts acknowledge that the potential for iSCSI rises as performance moves from Gigabit Ethernet to 10 Gigabit Ethernet. 'With five times the bandwidth of most FC products sold today, 10 Gigabit Ethernet currently sits quietly in the background - an inevitable giant in waiting,' said HP's Li.
On the other hand, it is also worth noting that FC prices will continue to come down as they have done over the years and that performance will also improve as the current standard of 2 Gbps moves toward 4 Gbps. As is so often the case, it all points to a future of rising competition between the two technologies.