StoneFly virtualizes IP SANs

By Dave Simpson

Last week, start-up StoneFly Networks began shipments of storage virtualization appliances designed specifically for IP storage area networks (SANs) based on the emerging iSCSI protocol. IP SANs enable users to build block-level storage networks using standard TCP/IP LANs, providing an alternative to direct-attached storage, Fibre Channel, and network-attached storage (NAS).

Although virtualization has many meanings (see the Special Report in this issue, p. 35), in the context of StoneFly's appliances, virtualization refers primarily to volume management, according to Allen Yuhas, StoneFly's president and CEO.

"We prefer the term 'logical volume management,' " says Yuhas. "Users can create logical volumes from physical volumes and manage the logical volumes as if they were direct-attached SCSI drives."

Yuhas says that his company's "Storage Concentrators" are targeted at end users that have not yet implemented SANs based on Fibre Channel due to cost and/or complexity reasons. The devices are designed for departmental-level SANs in small to medium-sized businesses.

"StoneFly is enabling iSCSI and simplified, low-cost SANs that will be easier to manage," says Arun Taneja, a senior analyst with the Enterprise Storage Group consulting firm.

The release of the iSCSI appliances coincided with Cisco's shipments of iSCSI switches that include eight Fibre Channel ports and two Gigabit Ethernet ports (see "Cisco enables low-end IP SANs," on p. 1).

According to a poll of InfoStor readers who have already implemented a Fibre Channel SAN, 41% are considering implementing an IP SAN based on iSCSI (see figure).

Among readers who have already implemented a Fibre Channel SAN, 41% are considering an IP-based SAN based on the iSCSI standard.
Click here to enlarge image

StoneFly's virtualization appliances, or routers, are available in two configurations: the i1000 and i1500, priced at $7,995 and $9,995, respectively. Both 1U units provide virtualization, Gigabit Ethernet connectivity, and three SCSI ports. (Future implementations will support Fibre Channel and native iSCSI target devices.) The i1500 adds high-availability features such as dual hot-swappable power supplies and local RAID mirroring.

The virtualization capabilities of the i1000 and i1500 come from the company's proprietary StoneFusion software, which provides storage device aggregation and iSCSI packet routing, a storage mapping layer, and a relational database that tracks physical data locations. The devices also provide iSCSI-to-SCSI bridging.

The in-band (e.g., in the data path between hosts and storage subsystems) appliances can be used with only host-level iSCSI software drivers or with host cards that offload TCP/IP and iSCSI protocol processing. At press time, StoneFly had tested its appliances with cards from Intel (which is an investor in StoneFly) and was testing compatibility with cards from Alacritech.

Later this year, San Diego-based StoneFly will add a number of layered software applications, including replication, snapshot, and mirroring. At that point, the iSCSI appliances will compete with existing products such as FalconStor's software-based IPStor.

StoneFly plans to sell its appliances solely through the channel and has signed a one-year exclusive agreement with distributor Tech Data.

This article was originally published on June 01, 2002