Clariion

Clariion

Company type	Product line
Industry	Computer storage
Predecessor	HADA (High Availability Disk Array)
Founded	1992
Founder	Data General
Defunct	2011
Fate	Phased out in favor of EMC VNX Series
Parent	EMC Corporation (from 1999)

Clariion (stylized as CLARiiON) was a SAN disk array that is no longer in production, initially created by Data General in 1992 and subsequently produced and marketed by EMC Corporation from 1999 until 2011. Serving as EMC's solution for entry-level to midrange SAN storage arrays, Clariion was phased out in favor of the EMC VNX Series in 2011, which combined the Clariion and Celerra product lines into a unified platform.

The final iteration, the CX4 series released in 2008, offered front-end connectivity through both fibre channel and iSCSI, while its fibre channel back-end delivered 4 Gbit/s bandwidth utilizing FC-SCSI or SATAII disk drives. The EMC Celerra NAS system shared the Clariion’s X-blade storage processor architecture.

Initially known as HADA (High Availability Disk Array), Clariion was among the pioneering commercial RAID storage solutions. It was first integrated with Data General’s Aviion systems before becoming broadly available starting in 1994. Data General set up a dedicated division for Clariion and marketed it as an OEM product, which expanded its market presence despite overlapping with Aviion internally. This approach boosted sales volume and brand awareness, ultimately leading to EMC’s acquisition of Data General’s storage division in 1999.

In 2011, EMC introduced the VNX series (internally referred to as CX5) to streamline its storage portfolio, resulting in the retirement of both Clariion and Celerra by early 2012.

History

The development of the Clariion disk array commenced in the early 1990s when Tom West—noted in the Pulitzer Prize-winning book The Soul of a New Machine—convinced Data General to pursue this project. West recognized an opportunity for sophisticated, open-standard data storage devices amid competition from companies like Digital Equipment Corporation with their StorageWorks line.

Patented in 1994, Clariion introduced several innovations that became industry norms, such as optional hot swapping, drive guide rails ensuring reliable electrical connections, and locking mechanisms securing drives within the enclosure. It was also the first in the industry to implement a dual active-controller architecture, mirrored write cache, comprehensive system redundancy, and hot repair functionality.

The Clariion family expanded into SCSI disk arrays accommodating between 7 and 30 slots. In 1997, Data General incorporated Fibre Channel technology with the FC5000 model, employing a Fibre Channel Arbitrated Loop interface that doubled SCSI throughput and was pioneering in implementing RAID 5 on Fibre Channel drives.

This platform evolved into a higher-performance and more scalable midrange storage solution, culminating in the FC5700 under Data General’s stewardship. Following EMC’s acquisition of Data General, development accelerated with new releases such as the FC4500 and FC4700 models, including the IP4700 variant that supported IP-based storage access.

By 2011, EMC had introduced its initial CX series models (CX200, CX400, CX600), followed by enhancements that increased processing power and bandwidth resulting in models like CX300, CX500, CX700 along with a low-cost SATA-based AX100 (later upgraded to AX150). In 2003, Clariion became the first storage system certified to meet NEBS standards.

In May 2006, EMC launched the third-generation CX3 UltraScale series (CX3-20, CX3-40, CX3-80), notable for utilizing end-to-end 4 Gbit/s Fibre Channel and PCI-Express technologies. The lineup grew further in 2007 with the addition of the entry-level CX3-10 model.

Most Clariion units up to the CX-4 generation operated on a customized version of Windows XP Embedded.

Architecture

The Clariion system is constructed on an Intel-based platform and operates two concurrent environments: a management interface running either Windows XP Embedded or a streamlined version of Windows Server, alongside the proprietary UNIX-derived FLARE software that handles primary data operations. The fourth generation employs 64-bit Windows Storage Server, whereas the third generation utilized 32-bit Windows XP. Its hardware design features a half-width 1U or 2U module known as an X-blade, with two such units installed side by side within each storage processor enclosure to provide a fully redundant active-active configuration. Both processors actively process requests and serve as failover partners, presenting the storage array to initiators in an active-passive manner. Additionally, an integrated uninterruptible power supply (UPS) safeguards data during power outages.

Storage connectivity is established via fibre channel, with initiators linking through fibre or IP based on the setup. The back-end architecture supports up to 120 drives per loop, organized within Disk Array Enclosures (DAEs), each containing 15 drives.

The FLARE operating system is stored on the initial four disks of the first DAE, which is powered by the UPS. In the event of a power failure, this area temporarily holds write cache data to maintain data integrity when power is restored.

Management of Clariion arrays is commonly conducted through Navisphere software, which is Java-based.

The UltraFlex series in its fourth generation introduces modular I/O components that allow for pluggable IP or fibre connections, providing scalable expansion options for both front-end and back-end interfaces throughout the lifespan of the array.

Optional licensed software enhances capabilities with features such as SAN replication, Quality of Service (QoS), and snapshot functionality.

Unique issues

Clariion's dual-controller design employs an active/passive model with mirrored write caches but restricts each LUN to a single active controller. This configuration frequently led to one communication path appearing inactive, prompting LUN reassignment—known as trespassing—to the alternate controller. Such trespassing could degrade I/O throughput and occasionally cause controller failures on earlier models like the 4500 when linked directly to multiple high-demand hosts.

Although controller crashes became infrequent following widespread adoption of Fibre Channel fabrics, trespassing remained an issue until firmware updates incorporating ALUA support were released around 2008.

AX series

The AX series represents Clariion’s entry-level disk array offerings.

As of February 2011, two models are available: the AX4 and AX150. The AX150 accommodates up to 12 Serial ATA drives with capacities of 250, 500, or 750 GB, delivering throughput rates of 150 MB/s for 250 GB disks and up to 300 MB/s for larger disks, optionally supporting NCQ. Supported RAID configurations include RAID 5 (minimum three disks) and RAID 1/0 (minimum four disks). Fibre Channel interfaces provide transfer speeds up to 2 Gbit/s, while iSCSI connections reach up to 1 Gbit/s. The AX150 is offered in four variants differing by connection type and number of controllers.

The AX4 succeeds the AX150, supporting up to 60 Serial ATA or Serial Attached SCSI drives when equipped with an Expansion Pack; its base configuration supports 12 disks. It offers either iSCSI or Fibre Channel connectivity, with Fibre Channel speeds reaching up to 4 Gbit/s.

Model	Connection	Controllers	Speed	Supported disks
AX150	FC	2	2 Gbit/s	12
AX150SC	FC	1	2 Gbit/s	12
AX150i	iSCSI	2	1 Gbit/s	12
AX150iSC	iSCSI	1	1 Gbit/s	12
AX4-5F	FC	1 or 2	4 Gbit/s	12 (60 with Expansion Pack)
AX4-5I	iSCSI	1 or 2	1 Gbit/s	12 (60 with Expansion Pack)

CX series

The CX lineup accommodates both SATA and Fibre Channel drives, offering RAID configurations such as 1/0, 0, 1, 3, 5, and 6, which can be arranged within disk groups.

Available models come in Fibre Channel versions (up to 2 Gbit/s) and iSCSI variants (up to 1 Gbit/s), with the CX700 exclusively supporting Fibre Channel. Models featuring iSCSI connectivity are identified by an "i" suffix in their names, for example, CX500i.

Model	Maximum FC hosts	Maximum disk drives	Starting capacity	Maximum capacity (TB)
CX300	64	60	365 GB	27 TB
CX500	128	120	4 TB	59 TB
CX700	256	240	~4 TB	119 TB

CX3 series

The CX3 family comprises the CX3-10, CX3-20, CX3-40, and CX3-80 models, with interface types denoted by "i" (iSCSI) and "f" (Fibre Channel) suffixes.

Model	Maximum FC hosts	Maximum disk drives	Starting capacity	Maximum capacity (TB)
CX3-10	64	60	1 TB	60 TB
CX3-20	128	120	1 TB	120 TB
CX3-40	128	240	1 TB	240 TB
CX3-80	256	480	1 TB	480 TB

CX4 UltraFlex series

The CX4 UltraFlex series presents models differentiated by maximum disk counts (both SATA and Fibre Channel) along with iSCSI or Fibre Channel connectivity options. The connection between the Fibre Channel interface and storage processor utilizes a PCI Express link capable of delivering up to 4 Gbit/s, whereas iSCSI interfaces support speeds up to 1 Gbit/s. All current models are compatible with RAID levels 0, 1, 1/0, 3, 5, and 6, enabling mixed RAID group configurations.

Each system in the CX4 series includes dual-redundant hot-swappable components such as storage processors, mirrored cache backed by batteries, and power supplies. Host connections are supported via both Fibre Channel and iSCSI protocols.

Notable enhancements in the CX4 UltraFlex range include integration of solid-state flash drives, a 64-bit FLARE Operating Environment, and PCI-Express based SLIC I/O cards. The CX4-480 and CX4-960 introduced fibre channel solid-state flash drives that provide substantial performance improvements as EMC’s Tier-0 storage tier. The upgraded FLARE OS supports Storage Processors powered by 64-bit Intel Xeon CPUs. PCI Express SLIC I/O cards offer adaptability for future technologies including 8 Gbit Fibre Channel and 10 Gbit Ethernet/iSCSI.

Model	Memory	Front-end FC ports	Front-end iSCSI ports	Back-end ports	Maximum HA Hosts	Maximum disk drives	Maximum capacity	Flash Drive Support
CX4-120	6 GB	4	4	2	128	120	120 TB	Yes
CX4-240	8 GB	4	4	4	256	240	231 TB	Yes
CX4-480	16 GB	8	4	4	256	480	939 TB	Yes
CX4-960	32 GB	8	4	8	512	960	1899 TB	Yes