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4Gbps Fiber Channel-to-SAS controller to support massive scalability

Posted: 10 Aug 2005 ?? ?Print Version ?Bookmark and Share

Keywords:ario data networks? sanario fs? raid controller? redundant array of inexpensive disk?

Supports SAS and SATA disk drivesSerial I/O vendor ARIO Data Networks is pre-announcing its SANARIO FS, a RAID (redundant array of inexpensive disks) controller.

Based on an embedded 500MHz RISC chip, it will support both SAS (Serial Attached SCSI) and SATA (Serial ATA) disk drives. The SANARIO FS will pack dual 4Gbps host paths, and will support SAS, SATA II, and SATA I disk connectivity. It's expected to be priced at about $2,100.

Support for both SAS and SATA disk connectivity will let you host multiple tiers of data on a single massively-scalable system. You can use the SAS drives for primary storage applications (such as transactional databases), and the SATA drives for secondary applications (such as disk-to-disk backup).

An industry-first
While this product is slated to roll out by year's end, ARIO Data is laying claim right now to being the first independent RAID controller vendor to announce a Fiber Channel-to-SAS controller.

The controller supports a 4Gbps Fiber Channel host interface and a 3-Gb disk drive connection. The controller also offers native support for Snapshot, RAID 6, and the SMI-S (Storage management Initiative Specification) open industry management standard.

A word about SAS. It represents the next generation of high-end disk drives, replacing conventional SCSI (Small Computer System Interface) drives for high-end applications. Unlike SCSI, which only supports 16 drives on a host bus, SAS supports up to thousands of drives per SAS interconnect.

A growing family
The new SANARIO FS joins ARIO Data's SANARIO FC RAID controller that features a 4Gb Fiber Channel host interconnect to a 4Gb Fiber Channel disk interface. The new SANARIO FS also complements the firm's SANARIO FSR (a Fiber Channel-to-SATA II RAID controller), the SANARIO FST (a 2Gbps Fiber Channel-to-SATA I JBOD controller), and the SANARIO FST II (a 2Gbps Fiber Channel-to-SATA II JBOD controller).

For its part, the latest SANARIO FS's host interface supports point-to-point, full fabric, and arbitrated loop configurations to a host. It also imparts the capability of auto-negotiating to support older 2Gb and 1Gb Fiber Channel standards. With dual 4Gb host support, the controller provides dual active/active operation for high performance, as well as controller failover/failback for subsystem availability.

With the failover/failback ability, if one controller fails, another can manage and run an entire subsystem, keeping data available to hosts and ensuring the reliability of that data.

The SANARIO FS supplies sixteen SAS channels to which SAS, SATA II, or SATA I drives can be connected. For higher performance environments, the use of SAS disk drives provides maximum bandwidth and I/O for data intensive applications.

Where cost is primary, or where the use of secondary storage for ILM (information lifecycle management), nearline storage, CAS (content addressable storage), or disk-to-disk back-up deployments are needed, the SANARIO FS supports the use of more cost-effective SATA disk drives. That can dramatically lower subsystem cost and total cost of ownership.

Thousands of drives
The SANARIO FS also supports the intermixing of SAS and SATA disk drives within the same enclosure. With its standard 4x-wide SAS expansion port, the product can be expanded with additional enclosures and subsystem configurations supporting thousands of disk drives.

At the board level, the new controller is powered by an Intel IOP331 I/O processor using Intel's XScale Technology. It supports RAID levels 0, 1, 3, 5, 6, 10, 50, and 60, while supporting up to 64 RAID groups per controller of up to 16 disk drives in each RAID group. Capabilities also include variable stripe size, read-ahead caching, and dynamic cache allocation (all contribute to improved I/O performance).

In addition to failover/failback features, the SANARIO FS also includes capabilities to guarantee data integrity. These features include mirrored cache, cache coherency, dual controller heartbeat, and automatic and transparent rebuild of failed disk drives in the background. You also get support for local and global sparing of disk drives, battery back-up support, and background re-assignment of bad data blocks on disk drives attached to an array.

For heterogeneous storage networks
Designed for deployment in heterogeneous storage networks, the SANARIO FS also incorporates both host-to-LUN (logical unit number) mapping and host-to-LUN masking to provide consistent data through the controllers in a dual-active configuration.

What's more, all of the SANARIO FS's data buses contain parity information for data protection. Topping that, the data cache memory is ECC (error correction code) protected, and is architected with a battery back-up unit to safeguard data in the cache in the event of a power loss.

The SANARIO FS also provides native support for RAID level 6, enabling non-stop operation even in the event of two disk drives failing in the same RAID group. With the industry movement to the use of less-reliable, but more cost-effective SATA disk drives, coupled with larger disk drive counts per array at ever larger disk drive capacities, this capability is becoming a mandatory requirement in today's subsystems.

RAID levels 1, 3, and 5 can only protect against a single drive failure per RAID group. They therefore don't provide the same level of data availability and fault tolerance as a RAID 6 deployment. By giving you RAID 6 functions, arrays created by the SANARIO FS can tolerate the failure of two disks in a RAID group and still deliver continuous data availability to the host.

Moreover, thanks to firmware and hardware parity regeneration, data is protected even if two disks in a RAID group fail. Through the use of RAID 6, and the hierarchical RAID implementation of RAID 60, the SANARIO FS provides maximum data reliability and availability.

Snapshotting, too
In addition to RAID 6, the SANARIO FS also provides for Snapshot capability. This technique supports the creation of an instantaneous point-in-time copy of a selected array in a storage subsystem. The snapshot preserves the array's image as it existed at the time of the snapshot so that the storage subsystem can continue to be used for primary storage, while other users manipulate the point-in-time/snapshot copy.

The most common usage of this feature is to permit a back-up of an array to proceed without taking the array offline, using the snapshot created to provide the backup source. Other applications that take advantage of snapshot capability include business continuity, software application development, decision support systems, and test functions.

Management, configuration, monitoring
The SANARIO FS also packs several features designed to provide network administrators with management flexibility. For example, the controller includes the company's on-line RAID expansion tool suite. It lets administrators add drives to existing arrays and re-stripe data across all driveswithout taking the array off-line.

The controller also supports immediate RAID availability, which brings an array on-line in a matter of seconds, and features non-disruptive firmware downloading for the controller, enclosure management, and attached disk drives.

Finally, the SANARIO FS controller integrates ARIO's RAID Manager software. This software is billed as a Java-based enterprise RAID management software application. Through its graphical interface, you can configure, manage, and monitor your RAID system.

The RAID Manager includes SMI-S support, remote event notification, error detection, and enclosure management and monitoring through SES (SCSI Enclosure Services). The software also supports controller and disk drive hot-plug and hot-swap.

In OEM applications, the RAID Manager supports the ability to add customization to differentiate the product. You can alter the screen's color scheme, icons and graphics, and change color and texture combinations.

Again, ARIO says its SANARIO FS will be available for OEM qualifications in the fourth quarter of this year. The company expects storage subsystem vendors to come to market with products powered by the controller in the same quarter.

- Alex Mendelsohn

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