IP adds value to enterprise storage

While iSCSI has been slow to catch on, Fibre Channel over IP is becoming the technology of choice for enterprises deploying disaster recovery over long distances, says Prashant L Rao

Fibre Channel over TCP/IP is gaining momentum as a more efficient way of gaining disk independence, says Idris Vasi

iSCSI (Internet Small Computer System Interface) is the basis of what is called the IP SAN. Through this protocol it is possible for servers to access Fibre Channel storage arrays over a LAN or WAN. On the face of it, it seems that iSCSI holds all the cards and that it should have caught on like wildfire. It hasn’t, and therein hangs a story.

iSCSI adoption has been slow for many reasons. “A year back there was no standard in iSCSI, every vendor had his own proprietary implementation of the protocol,” says Sandeep Dutta, director-Strategic Partnerships & Marketing, Network Appliance India.

“The ratification of the standard took longer than expected,” says Idris Vasi, director, Optical & Storage Networking, Cisco Systems APAC. Another factor slowing iSCSI adoption has simply been a lack of products. Avijit Basu, marketing manager-Network Storage Solution, HP India says, “There aren’t too many iSCSI products that are tested and certified.”

FCIP/iFCP more popular: DR is killer app

Fibre Channel has a maximum reach of 10 kilometres. For anything beyond that, say deploying a disaster recovery (DR) set-up across two cities, you will need to tunnel Fibre Channel over IP. Two protocols let you do this, FCIP (Fibre Channel over TCP/IP) and iFCP (Internet Fibre Channel Protocol).

“There is a lot of demand for FCIP in DR, back-up and consolidation of SAN islands. It is gaining momentum as a more efficient way of gaining disk independence,” says Vasi. FCIP is gaining traction with financial institutions for disaster recovery and connecting SAN islands. “Our customers are using FCIP for DR or business continuity using pipes ranging from 4 Mbps to multiple E3s,” says Arun Rawtani, country TSG manager, EMC-India.

Consider a company that has a primary site and a secondary back-up location. Both sites have fibre channel SANs. Both are connected using an E1 or bigger IP data pipe. One way out is to use CNT UltraNet Edge Storage Routers to hook up both SANs to the IP circuit. The FC connection from the SAN goes into the edge router and Gigabit Ethernet comes out onto the IP circuit. The channel extender takes care of security, compression and load balancing.

iSCSI vs. FC: A tale of two technologies

iSCSI as a technology is well suited to delivering low-cost SANs. Keep in mind, however, that these IP SANs cannot match a traditional Fibre Channel SAN in performance. They are suitable for applications that aren’t mission critical in nature. V Vivekanand, sales director-India, Hitachi Data Systems says, “You need a high performance fibre channel SAN for real-time applications running on enterprise class servers such as the Sun Fire 15000 that pump 70 to 90 Mbps of data into the storage network. For low workload servers that generate 5 to 10 Mbps of throughput, the cost of fibre channel HBAs (host bus adapters), switching fabric and port connectivity is exorbitant. For non-critical applications that need to be integrated into a SAN, iSCSI is a good choice.”

At the branch office or departmental level, where a Fibre Channel SAN might be too expensive to consider, an IP SAN based on iSCSI can be a good fit. “A small department in a large enterprise can’t afford a SAN. If they have a database to implement on the network, iSCSI is the best option for them,” says Dutta.

Today, iSCSI is being used to deploy applications such as billing and CRM. As with SCSI, iSCSI offers a block interface suitable for applications, including databases and streaming media. iSCSI can complement NAS in cases where the applications need to see disks locally, for instance, in Microsoft Exchange.

“An organisation that has hundreds of servers identifies critical applications and puts their storage on the SAN. Other applications such as e-mail and internal financials or HR databases may or may not be performance critical. You don’t put these on the SAN, as the cost of Host Bus Adapters and Fibre Channel switches is huge. The per-terabyte cost is much higher than in low-end systems,” says Rawtani.

The SAN of tomorrow?

The iSCSI 2.0 standard is expected in February 2003. That should spark greater interest in this technology as it matures. iSCSI has its advantages. It offers any to any connectivity and lets you use commodity Ethernet, Fast Ethernet or WiFi. As IP is a commodity technology, component costs are lower than that of FC. For instance, Alacritech’s TCP Offload Engine is three times cheaper than a FC HBA. An enterprise can use these cards to set up block level I/O starting with iSCSI and migrate to FC later (or go for a mix of both). As iSCSI takes advantage of existing IP networks by melding storage arrays with a LAN or WAN, companies won’t have to shell out money to upgrade existing hardware or train employees on a new technology.

“iSCSI will take some time to catch on. We should see good growth by H2 2004,” says Rawtani. HP expects iSCSI to start taking off in eight to 12 months in India with large enterprises being the early adopters. IDC believes that 2005 will be the key year for iSCSI in India.

While Microsoft has announced support for iSCSI across its Windows desktop and server lines and Linux support exists, commercial UNIX support for iSCSI is not widely available at this point of time. That said, Windows Server OS is the key operating environment for almost all small organisations, 74 percent of medium and 78 percent of large organisations with a SAN. (Source: IDC).

“It will take longer for iSCSI to make its mark in the data centre. You can’t rule it out either as performance on IP is going up,” says Rawtani. Gartner believes that iSCSI products won’t challenge Fibre Channel SANs until 10 Gbps Ethernet is widely available.

FC strikes back

There is a phenomenon that could derail the iSCSI bandwagon before it gets rolling. Entry-level SAN prices are falling. Today, a basic SAN of 500 GB can cost as little as Rs 7 to 7.5 lakh. “Last year, we could not think about talking to a customer about a SAN for less than Rs 15 lakh,” says Shailesh Agarwal, country manager-Storage, IBM India.

Fibre Channel SAN shipments are rising with IBM alone installing around 40 every quarter. The fact is that FC SAN prices are constantly dropping, striking at the roots of one of the key factors in favour of iSCSI—price. Vendors are adopting technology such as Serial ATA to bring down prices—you can fit SATA hard drives into an IBM ESS box.

Whether iSCSI and the IP-SAN make SAN affordable or the falling prices of FC SANs make them affordable to enterprises, both large and small, SAN penetration can only go up. According to IDC, only 27 percent of large organisations, 13 percent of medium organisations and 10 percent of small organisations presently have one or more SAN in use. That number is bound to go up substantially if the rest of the APAC is anything to go by—markets such as Australia have seen over 50 percent of organisations adopting SANs.

iSCSI/FCIP in the Indian enterprise
Company	Enterprise customers using IP-SAN technology
EMC	Tata Teleservices uses FCIP. Reliance and Whirlpool are using iSCSI.
Hitachi	Data Systems HDFC Bank and the National Informatics Centre are using iFCP for disaster recovery.
HP	BPCL and ICICI Bank are using Fibre Channel over IP using Director class switches.
Network	Appliance HDFC Standard Life uses iSCSI.
	Source: Vendors

iSCSI vs. Fibre Channel
iSCSI	FC
Gigabit/Fast Ethernet network card	HBA (Host Bus Adapter)
LAN switch	FC SAN Switch
Easy to manage.	Complex to manage.
1 Gbps	2 Gbps
The load of processing storage packets can be high unless you use a TCP/IP Offload Engine.	No performance issues on the server.
Low-cost, can handle moderate workloads.	High cost, high performance.

prashant@expresscomputeronline.com