Raiders of the Cost Bark: A Review of nStor RAID Array CR8e

The most common form of RAID, a J-BOD (for "Just a Bunch of Disks"), really isn't a RAID at all, but, because it is the most simple and familiar form of mass storage, it is often the first step a user will take in augmenting an NLE's capacity. The J-BOD is a self contained box with a power supply, several drives, usually connected as a SCSI chain, and a fan or two.

We recently built such a box to augment our DPS Perception system by buying a $300 enclosure with two fans and a 400 watt power supply. We installed a 23 gig Seagate Panther, three 4 gig Seagate Barracudas and a 9 gig Seagate Elite (everything we had in the shop at the time) and cabled them in a chain that ran back to the host computer through a very thick, short SCSI I cable. In the Perception program, the drives come individually and are addressed sequentially. To backup our materials, we used Windows Explorer or, if our jobs were extremely large, we crossed our fingers and risked the entire 58 gigs unduplicated. Compared to the offering of this review's key product, the nStor CR8e, a J-BOD is as crude as a Neanderthal's stone wheel is to a Perelli radial.

Real RAIDs, like nStor's CR8e take the contents of a J-Box and allow the user to manipulate the data in a number of ways that result in a much higher degree of safety from data loss, and often, a much higher throughput of data. There are five ways of configuring a RAID (easily remembered, the range from RAID 1 to RAID 5) and nStor's product allows the user to configure the CR8e as any of those configurations, even while the computer is working on data stored on the RAID.

When considering RAIDs for nonlinear editing, it is important to remember that RAIDs were originally developed when media files were not the prime design consideration. Originally, RAIDs were used by large servers for alphanumeric data storage and backup, such as that used by a financial institution. We video editors have come on the train a little late. Consequently, many RAID manufacturers are not prepared for the sudden market we represent. nStor seems to be an exception, having taken space at the recent NAB and SIGGRAPH shows and their literature and product education materials reflect an awareness of our niche's need to learn and apply RAID technology in a new way.

The nStor CR8e is composed of seven internal components: disk drives (up to 8), fault LED, power switch, SAF-TE cad, hot-swappable cooling fans, hot swappable power supplies and a configuration module (either dual or single bus). The fault LEDs are mounted, in alignment with their respective drive bays, on a lockable door on the front of the heavy gauge case. Amber indicates a failed or problem drive, green a good drive, blinking green an idle drive. The recessed power switch is located within the enclosure to prevent inadvertent shut-downs. The SAF-TE card is the control and monitoring subsystem that provides the central data link to the host computer.

The speed of the cooling fans are thermally controlled (by two sensors mounted between the drive slots) to reduce noise and increase temperature efficiency. The SAF-TE card monitors each fan's speed via tach pulses. In the event of a fan failure, an audible alarm is activated, the status light on the troubled fan goes amber and the control panel identifies the problem. The fans can be changed while the system is in operation.

Our unit came equipped with three, 150 watt hot swappable power supplies. The power supplies share power jointly to the system so that if any power supply fails, the remaining units immediately make up the loss. In the even of a failure, the LEDs, alarm and operation panel inform the operator immediately.

The RAIDs Arrayed

RAID levels from one to five relate to how the various drives on an array store and backup data. A basic rule of RAIDs is that they must all be composed of the same kind of drives, such as eight 4 gig drives or six 9 gig drives. There are five primary RAID levels:

RAID 0: Striped disk array without fault tolerance: This level makes all the drives into one large drive. Although it is said that this level "stripes" data across all drives, it should not be construed that the data is continuous from one drive to another. A single file may be broken up into many segments and distributed on any or all the disks in the system.

RAID 0 is the most capacity-efficient RAID, but because it does not provide backup redundancy, if one drive in the array fails, all data on all drives is lost. RAID 0 should be used on systems where optimum performance is required, but where fault tolerance is not an issue, such as full motion video access where the backup tapes are available and where re-acquisition time (such as for an on-demand playback system) is not a serious factor.

RAID 1: Mirrored drives: This level uses paired disks to create an identical copy of each drive on a duplicate drive. The mirroring provides 100% duplication of data. Writing to a RAID 1 will be slower than writing to a single drive, but nStor's SAF-TE controller enhances read performance by simultaneously reading both drives.

RAID 1 is the most secure level of data storage, but the cost of maintaining it are high because twice as many drives must be purchased to achieve redundancy. Because of the reduced access speeds, RAID 1 may not be suited to your video project studio.

RAID 10 (RAID 1 + RAID 0): Striping and Mirroring: This level provides better access rates than RAID 1, because it employs striping each pair of drives. The operator still needs to purchase twice the amount of data required to achieve redundancy, but this level may suit some video editors whose compression hardware does not require the highest levels of throughput.

RAID 3: Striping with Dedicated Parity Disk: Parity is defined as extra data that is added to a data stream that assists in rebuilding lost information. By adding parity to a RAID 0 configuration, the data stored on any one disk in a striped array can be recovered from the remaining disks. RAID 3 takes one of the drives in the system and dedicates it to parity storage. This results in a fast and economic array with high storage yield (eight 4-gig drives will allow 28 gigs of secure storage), fast access and high security. The only risk is that both the parity drive and one other drive will fail at the same time, resulting in total data loss. Because a RAID 3 can only write one file at a time, it may cause bottlenecks that are unsuitable for video editing.

RAID 3 is excellent for image storage and manipulation and may be used in most forms of video editing if the write speed for your system can accommodate the write-time limitation.

RAID 5 is my favorite, combining economy with safety. RAID 5 allocates a certain amount of the RAID's total storage capacity to store information that will allow it to quickly rebuild the data of any one physical drive on the system. This means that eight 4-gig drives will yield 28 gigs of useable storage. The four gigs required to backup any lost drive on the system is spread across all eight drives. Your risk is that more than one drive may crash at one time.

The nicest thing about the nStor CR8e is that you can switch from any RAID level to another as your needs on a particular job dictate. For instance, you might start out with a fully redundant RAID X on a job that is growing and then switch to RAID 5 if you need more than half your total drive capacity.

The Test Platform

We originally thought we would test the nStor CR8e on our three DPS Perception systems, but this was not feasible for two reasons. First, the current shortage of PCI slots on Pentium 1 motherboards does not allow for the addition of the nStor PCI controller card while maintaining the other cards that a Perception system requires. Second, the Perception cards, which require media storage to be connected directly to the Perception's proprietary SCSI-1 bus, can only use a J-Box style RAID array, thereby preventing the use of 90% on nStor's technology.

We therefore obtained a test platform based on the Targa technology of Truevision Inc. which combines the sound card and the video card in one and allows for media storage on any SCSI format drives connected to the motherboard's PCI bus.

Our test platform was a dual Pentium Pro, Compaq Deskserver 6000, equipped with the Targa 2000 RTX/DTX card, a 4-gig Seagate Barracuda (for system programs) and a 9-gig Seagate Cheetah (for audio media and NLE programs).

Installation

Installation of the nStor equipment was relatively easy for a first timer, using the excellent documentation package and software-based help screens. The CR8e allows either single or dual channel installation, which means that the box can be configured as one or two RAIDs in one enclosure.

Physically, the CR8e is delivered to order as an independent case, a PCI board for the host computer, appropriate cabling and whatever assortment of drives you care to install. We opted for nStor's suggestion of eight 4-gig Seagate Barracudas (spinning at 7,500 RPM). NStor's RAID will also work with Seagate's Cheetah line which spins even faster (10,000 RPM) delivering a throughput of 20 MBs. The unit we tested retails currently at $14,585 after a recent discounting from a list of $22,745 or 36%!

Assembly is stupid easy and consists of pushing each drive into a drawer and then sliding the drawer into the RAID box until it locks into position. A strong, metal handle allows for the drive to be removed at any time, even during data access, which is called, "hot swapping."

The manufacturing of the CR8e is quite impressive with heavy gauge metal throughout, highly redundant cooling, sensors, alarm systems and a large alphanumeric LCD panel that displays English language messages relating to the health of the system.

The RAID is configured to the host system during the black screen boot of the computer and actually accesses nStor's own motherboard bios. This produces an assortment of highly graphical screens that walk the user through RAID level assignment, drive configuration and testing and drive formatting, which, incidentally takes about 10 seconds for a 32 gig array!

Once the bios installation is complete, the host computer is booted and some floppy disk programs are loaded into Windows (95 or NT) that allow Windows Disk Administrator to see the array. Depending on how the array is configured, the drives then appear in Disk Administrator. Our 32 gig, RAID 5 array came up as one, 28-gig drive.

Application

Our immediate need for a RAID array is to test Avid's MCExpress for Windows and Discreet Logic's D-Vision 3.5 for press review. As we await the delivery of D-Vision 3.5, we proceeded to start a major project on MCX to test the RAID.

Initially, we ran into some problems which allowed us to test the technical support capabilities of nStor as well as those of Truevision and Avid. Running a multi-vendor system with no VAR in the loop is a daunting challenge, but happily, all three firms were cooperative and any pass-offs of problems were warranted. Avid engineers even interrupted their annual holiday season party to respond to my December 23rd pleas for help! And Avid does not recommend using any RAIDs but their own house brand, so we take our hats off to these New Englanders for whom the holidays are always treasured over business.

Our problem, incidentally, regarded data throughput speed. Avid has built in module that measures the access speed of the hard drive in numbers from 0 to 500 (with 320, the limit of the Targa board, being the highest practical). We eventually got our system working at 120 to meet our deadline for this article. This level was adequate for broadcast work and we believe with some tweaking we can get it higher.

In all other respects, the nStor array works faultlessly and appears to all Windows 95 and NT 4.0 systems as well as DOS as just another drive, albeit a 28 gig drive. We tried using the nStor to hold our ACT! database of client files (2,000 files of over 60 fields each) and it performed much faster than a single 4 gig drive. We tried taking a drive out of the array and got the usual software alarms and routines for rebuilding the array (no, we did not actually rebuild the array without the drive, but we felt confident that we could if we had to).

Finally, we tried running a complete client-intensive editing job, a short show reel for a public relations firm, on the nStor equipped system and there were no problems that our operator or our client noticed. The system performed as expected, providing a large storage capacity with faultless backup capability.

Eventually, we forgot the nStor was there (well, the client saw the box with all the lights and asked what that was, but otherwise it was forgotten), which is just what you want a RAID to do. You want to forget the drives and not worry.

System Safety

The culmination of making a risky situation completely secure is that it becomes unnoticed, forgotten. Having lived through many belly-wrenching experiences with faulty hard drives, lost data and panic stricken sessions, it was a true luxury not to have to worry about data anymore.

nStor's hardware, software, technical support and design philosophy eventually combined to lull us into the most desirable state of creativity. We used to always worry about the temperature in the computer room. Mike Bushey, of Bushey Virtual Construction, a California-based VAR informed us that every day a hard drive is worked at 2 degrees of heat above the optimum temperature, the drive will lose 6 months of its life expectancy. So, to be on the safe side, we chilled our rooms until clients wore their coats! Now we rest assured that if the heat gets too high in the nStor cabinet an alarm will go off and tell us how cold we have to make it (hasn't happened yet).

We used to worry about a power supply going down (So we kept a spare on the shelf, which was like having a fire extinguisher on the space shuttle. By the time you need it, you're dead.) No we know the nStor's double redundant power will kick in if necessary and fast enough that we won't know it happened (except for the alarm).

Recently, we even learned that nStor has developed a new software, called AdminiStore TM which is a remote administration manager that allows an authorized technician to monitor and manage all disk array subsystems from anywhere in the world, via the Internet. This will be a useful tool for animators who often leave their systems running unattended overnight and over weekends.

Conclusion

The addition of a RAID array is certainly in the future of every serious nonlinear editor. Many will no doubt opt to have their VARs do the heavy work and take the responsibility, but the effort of self-installation is both economical and highly instructive.

nStor, in our opinion, is one of the first RAID vendors to offer both a highly sophisticated product and a willingness to help nonlinear video editors exploit their admittedly arcane technology. While NLE may not represent a major market for nStor or its competitors and makes certain demands that other RAID purchasers do not require, nStor seems highly motivated to serve our industry and offer significant improvements in our job security and mental health. We applaud the launch of the nStor CR8e and look forward to other developments from this forward thinking company.

Evaluation

Meets the Need 10
Bang for Buck 9
Installation 10
Quality of Manufacturing 10
Quality of Software 9
Documentation 10
Ease of Use 9
Technical Support 10