Mixing Up Storage Networking


Competition between iSCSI and Fibre Channel proponents can get so fierce that it's easy to forget that IP storage does not have to be an either/or proposition. More and more storage vendors are supporting both protocols, even on their low-end and mid-range systems.


The trend probably has more to do with the need to integrate into mixed environments than with trying to avoid taking sides, but it is a strong indicator nevertheless that there isn't likely to be a single predominant storage network regime any time soon.


IBM is backing both protocols on its new Systems Storage N5600, which scales up to 262 TB and is the result of a deal with NetApp to rebrand its file appliances. The device is the mid-level offering between the N5500 and the N7600 appliances and offers advanced features like RAID 6, snapshot backup and thin provisioning.


EMC has brought dual-protocol functionality to the CLARiiON line with the new CX4 Series. The system supports a unique on-line expansion feature for both iSCSI and Fibre Channel, as well as a tool called UltraFlex, which can non-disruptively upgrade to 8 GB FC or 10 GbE, as well as Fibre Channel over Ethernet (FCoE). It can also accommodate the dynamic addition of I/O ports for VMware virtual infrastructures. EMC is avoiding Fibre Channel on the very low end, however, using SAS and/or SATA drives on the new Celerra NX4.


Sun users are likely to see new bridging technology for mixed environments. ATTO Technology recently gained Solaris Ready certification for its ExpressPCI host adapter and the iPBridge 2700 iSCSI-to-Fibre Channel Bridge. The device lets you integrate iSCSI into existing FC networks (up to 4 Gbps), allowing storage to be shared across both formats. The ExpressPCI adapter is a low-profile SCSI device that combines x4 PCIe with proprietary technology to enhance large-block data transfers.


The two protocols are also coming together on the chip level. 3Par recently introduced the InServ T-Class platform, an ASIC designed to offload storage provisioning tasks from the main processor. The system offers both iSCSI and Fibre Channel support, with gigabit Ethernet available for remote data replication. The device is available with four or eight storage controllers.


Despite these dual-protocol offerings, it's unlikely that the entrenched interests of either protocol will step back from the war of words accompanying both technologies' advancement into higher throughput versions. But the good news for users is that investment in one system or the other doesn't mean you're locked in for life.