By Lisa Coleman
LeftHand Networks recently began shipping an IP-based storage area network (SAN) solution that leverages existing Ethernet networks and provides high-end management capabilities without using Fibre Channel or iSCSI, according to company claims.
The IP SAN is a combination of LeftHand's Network Storage Module (NSM) hardware and Distributed Storage Matrix (DSM) software, which provides virtualization and management capabilities. The combo provides a scalable, fault-tolerant pool of storage that can be shared by all servers on a network. It can virtualize storage, replicate data, and provide snapshots and has capabilities for fail-over monitoring, data migration, and load balancing.
"Customers can put network storage modules directly on their Ethernet networks," says Bill Chambers, LeftHand's founder, president, and CEO. "The modules appear to the servers as though they're infinitely scalable local disk."
LeftHand Networks is also promoting the IP SAN as an alternative for users who cannot afford the cost or complexity of a Fibre Channel SAN. The system uses standard network interface cards (NICs) instead of host bus adapters (HBAs), works with standard Ethernet switches, and includes built-in virtualization software.
Chambers contends that the total cost of ownership is much lower than with a Fibre Channel SAN or even traditional network-attached storage (NAS). In addition, the system is easy to use, configure, and change, and it can be managed from a centralized console, says Chambers.
The NSMs are the primary building blocks of the IP SAN. They are modular storage devices that run the Linux-based DSM software. DSM drivers are available for Windows 2000; Linux and Solaris support are due within the next month. By adding NSMs in increments of 160GB, 320GB, or 480GB, the SAN can be configured with as much capacity as necessary. The IP SAN is priced from $15,000 for a 500GB configuration. A typical 2TB configuration is priced at $75,000.
Client software called Advanced Ethernet Block Storage (AEBS) is required on each application server accessing the IP SAN storage blocks. While the NSMs have the ability to run in a file-based mode, the system is only configured for block-based storage. However, users can enable file-level access by using a file server, or NAS head, to front-end the IP SAN.
Administrators can use LeftHand's Java-based Storage Control Console (SCC) to manage the NSMs. The SCC can also create clusters of NSMs, manage authentication of volumes and devices, and monitor all devices from a central point.
Snapshot functionality and replication is built into the system. Snapshots are made via point-in-time copies. Users can snapshot a volume while it's running and then mount it on the backup server and archive it to tape. Administrators can also specify replication levels. Replication is synchronous. For example, each change that occurs in a database is simultaneously replicated to as many locations as the users set up. q
LeftHand Networks' approach to IP SANs (left) does not require components such as iSCSI HBAs and targets, virtualization appliances, IP-FC gateways, and multi-protocol concentrators.