The market for iSCSI targets—devices to which servers read and write data—is dramatically different from the relatively barren wasteland we saw a few years back. But, considering the bright future eWEEK Labs saw for iSCSI when we first started testing prototype products in 2002, the maturation of the iSCSI target market has been painfully slow. Thats all changing, however, as new products have become available that prove iSCSIs promise.
The leading vendor in the iSCSI market was and is Network Appliance. This is not really surprising, considering the convoluted market forces at work. Unlike other large storage companies, which feared that iSCSI would cut into the lucrative revenues they were getting from the sales of their Fibre Channel storage products, Network Appliance did not have anything to lose by becoming an iSCSI pioneer.
In fact, iSCSI allowed Network Appliance to expand into the block-level storage market from its file-level NAS stronghold. Ironic as it sounds, considering the way in which it was done, Network Appliance has Microsoft to thank for putting it on the path to iSCSI. A few years ago, when Microsoft decided to limit Exchange support for NAS to performance-qualified products running Microsoft Windows Storage Server NAS platform, support for Exchange implementations that ran on Network Appliance NAS shares or another non-Microsoft NAS was effectively killed. Consequently, Network Appliance had to develop a block-level storage protocol to remain a major player in the e-mail storage market.
When iSCSI became ratified, Network Appliance was able to quickly replace its proprietary IP storage protocol with iSCSI, to become one of the first major vendors with an iSCSI storage system.
Large vendors such as EMC finally came out with storage units running iSCSI in 2005. One example is the entry-level Dell/EMC AX100i, which we used in our head-to-head tests of iSCSI and Fibre Channel. With starting prices as low as $5,000, EMC is marketing these units toward the lower end of the storage market, specifically to companies that normally would not be able to afford EMC storage.
Not to be outdone by the big boys, a handful of startups have been in the market since the beginning and are continuing to build momentum. The products we have seen from startup vendors are far more powerful than the previously mentioned AX100i, and while they are considerably more expensive (priced at more than $20,000), they bring enterprise-class functionality to the midrange of the market. EqualLogics PeerStorage Arrays, for example, have been in our labs twice and have proven to be not just competent but feature-rich—with clustering, snapshot and volume cloning capabilities, as well as replication over WANs coming as a standard feature.
Another iSCSI storage system startup that has caught our attention is Compellent, whose highly flexible Storage Center system can provide both iSCSI and Fibre Channel connectivity. Also worth mentioning is Lefthand Networks SAN/iQ software, which can be used to turn commodity servers into iSCSI targets.
Two other categories of iSCSI products make the technology even more compelling.
iSCSI storage routers can be used to hook iSCSI clients to a Fibre Channel storage system to take advantage of unused storage capacity. These storage routers also can be used to extend SANs across WAN links using iSCSI. All of the major SAN switch vendors, including Brocade, Cisco and McData, have competent products in the storage router space.
In addition, TOE (TCP/IP Offload Engine) cards and iSCSI HBAs are important add-on devices that have the potential to increase the performance of iSCSI storage systems. TOE cards take over TCP/IP processing chores, allowing server processors to focus on application loads. iSCSI HBAs are TOE cards that also have iSCSI initiator software integrated into the cards.