After 32 pages, we would first like to extend our admiration to the people who have read this entire article. Not only did you find a nice way of spending your time, you've also gained quite some knowledge about all possibilities and features available with Serial ATA technology. We have discussed the architecture of the various RAID implementations, you have been talked through the latest and greatest RAID components and you've seen a detailed view on the performance of eight of the most popular and most interesting SATA RAID solutions in desktop, workstation and server workloads. Furthermore, we have shown how the performance and features of the current generation SATA RAID adapters compares to the latest SCSI RAID solutions. This report has made clear that simplified comparisons based on characteristics such as port speed, bus or drive interface and the number of drives in a RAID array have absolutely no validity in real world situations. Each RAID implementation has different scaling characteristics, caused by differences in I/O processor and I/O controller performance, cache memory, available bus bandwidth et cetera. Performance is also greatly dependent on variables like cache strategies and specific RAID stack optimizations for block level striping, mirroring and parity calculation. You can't make judgements by simply looking at the numbers. Only benchmarks in realistic workloads will bring insight to the real world performance of the various RAID configurations.
Even more than the participants in our previous SATA RAID review, the adapters in this updated comparison make clear that Serial ATA is ready for the enterprise. The first class adapters in this review are offering everything you would expect from an enterprise RAID adapter: support for all essential availability features, professional management software and high performance - in some cases on the SCSI level. The intelligent RAID implementations are mostly direct derivatives of implementations already used in the SCSI world. These products are therefore comparable to SCSI RAID solutions, certainly now that native command queuing and enclosure management have been added to the Serial ATA II specification. The Western Digital Raptor WD740GD hard drives, which we used in our tests, were very reliable. During the last half year, the Raptors have performed more than a billion I/Os without a single failure. Thanks to the user-friendly and troublefree Serial ATA topology there where no connectivity issues. We have seen different behaviour from SCSI disk arrays in previous tests. Two of our Atlas 15K drives have failed and the troublesome bus connectivity has been a regular frustration.
Areca ARC-1120: highly recommended
In the group of eight SATA RAID adapters discussed in this article, there is one product standing out. The Areca ARC-1120, thanks to its 500MHz Intel IOP331 processor, 128MB DDR333 memory and Marvell SATA II controller, is without doubt the most powerful RAID implementation in this comparison. The powerful architecture of the ARC-1120 translates into exceptionally good performance. The ARC-1120 was invicible in the desktop and workstation workloads and even though the ARC-1120 fails to claim complete dominance in the server simulations, server performance was still outstanding. Issues with disappointing RAID 5 and RAID 10 performance in certain workloads have been effectively addressed by Areca. With the latest firmware, RAID 5 performance is excellent accross all benchmarks. Whether you use the adapter in streaming media servers, backup servers, database servers or mailserver, the RAID 5 performance is always top class and in many cases way ahead of the competition. Furthermore, the Areca ARC-1120 is rewarded for its broad driver support, its simple but effective webbased management interface and its excellent RAS (reliability, availability and serviceability) featureset, among which are support for online capacity expansion, online RAID level migration, optional Battery Backup Unit and a redundant flash chip. The Areca controllers are the only participants which have support for RAID 6, a RAID-level even more secure then RAID 50. The Areca ARC-1120 is pricey, but the price certainly is not unreasonable. The 3ware Escalade 9500S-8 is only a little cheaper, while it isn't as richly equipped and fails to reach the performance levels of the Areca ARC-1120. Dual channel SCSI RAID adapters are usually more expensive than the Areca ARC-1120.
Another advantage of Areca's products is the extensive range of SATA RAID products Areca is now shipping. The SATA RAID adapters are available in PCI-X and PCI Express configurations with 4, 8, 12 and 16 ports. Not satisfied with its current line-up, Areca will release 24-port versions in the first quarter of this year. Starting at the 12-port version, the adapters are featuring expandable cache memory and an ethernet interface. Thanks to the onboard network connection, the management software can be directly available over the network without the help of server-side software. The management interface is feature unique to Areca's products. There are no competitive Serial ATA RAID adapters on the market with this ability. The management interface is also a rarity in the world of SCSI RAID adapters. Expandable cache is only found on the 3ware Escalade 9500-series. Unfortunately, the cache performance of the 3ware adapters is way behind the Areca cards.
Areca ARC-1160 16-port PCI-X SATA RAID adapter
It can be considered quite an achievement that the unknown firm of Areca has been able to develop such a wide range of SATA RAID adapters in a short time. Adaptec is the only company to offer a 16-port alternative. The upcoming 24 port version will have no competition. In the first half of this year, Areca will extend its line-up of PCI RAID adapters with new promising products using Serial Attached SCSI technology. A great achievement if you realise that industry giant LSI Logic had to postpone the introduction of the MegaRAID SATA 300-8X, based on a similar implementation as the ARC-1120, by more than eight months. Although LSI Logic has extensive experience developing PCI RAID adapters, there will be only one model available for now. Areca is a company with a large potential, a name which we will undoubtedly encounter more often in the future.
For all mentioned reasons, the Areca ARC-1120 and its cousins from the Arc-11xx and Arc-12xx series are highly recommended.
RAIDCore BC4852: recommended
The performance of the RAIDCore BC4852 does not reach the high levels set by the Areca ARC-1120. Nevertheless, this hostbased RAID adapter shows very good scalability. The weakness of the RAIDCore BC4852 is its RAID 1 and RAID 10 performance, and its high CPU usage in workloads with a large amount of sequential write operations. In real world situations, the last remark should be no real drawback, since only a few applications will generate write rates of hundreds of MB/s. High performance dual processor systems will have more than sufficient processor power to handle the RAID logic. RAIDCore has succeeded in developing a stable and feature-rich RAID stack with user friendly management tools thanks to the self-tuning proporties of the RAID stack. Based on the good performance in our workload simulations, we can conclude that self-tuning indeed works very well. The price of BC4852 is attractive in comparison to 8-port intelligent RAID implementations like the Areca ARC-1120 and the 3ware Escalade 9500S08. For this reason, the RAIDCore BC4852 and its four port sibling deserve the title 'recommended'.
HighPoint RocketRAID 1820A: recommended
The HighPoint RocketRAID 1820A is rewarded for its exceptionally low price. With a price per port just above 30 euros, the RocketRAID 1820A is almost 70 percent cheaper than the RAIDCore BC4852 and even two and a half times cheaper than the Areca ARC-1120. The card doesn't develiver top performance - they RocketRAID 1820A frequently floats in the midfield - but nonetheless, the speed is sufficient for less demanding applications. Unfortunately, the RocketRAID 1820A lacks support for certain important features, online capacity expansion being one example. Because of the less sound impression we got from the HighPoint management software, and the narrow featureset, we advice against the use of the RocketRAID 1820A in professional servers. This card is very well suited for home users, though. Because of the excellent price/performance ratio, the RocketRAID 1820A deservers the title 'recommended'.
For several reasons, we will refuse recommendations on the remaing adapters in this comparison. The performance of 3ware Escalade 8506-8 is lagging far behind the competition. Moreover, it misses important features such as online capacity expansion, online RAID level migration and RAID 50 support. Besides a lacking featureset, the adapter is also priced too high. The 3ware Escalade 9500S-8 scores very good in the desktop and workstation RAID 10 benchmarks. With the exception of the database and mailserver scenarios, the server performance lags behind the competition. The Escalade 9500S-8 and the Escalade 8506-8 failed to perform in RAID 5. The Escalade 9500S-8 will continue to fall behind in terms of features as long as the promised firmware update is not released by 3ware. At this time, RAID level migration and online capacity expansion still haven't been implemented by 3ware. If all this would be offered for a reasonable price, buying the Escalade 9500S-8 could still be considered. Unfortunately, the high price of around € 600 stands in no relation to the performance and the featureset. We wonder if 3ware isn't on a dead end with its non-commoditized RAID implementation. The performance is disappointing, the featureset is not up to the standards of the competition and the architecture is out-of-date. While the Areca ARC-1120 already offers full Serial ATA II support, the Escalade 9500S-8 still doesn't feature native Serial ATA controllers. 3ware has to come up with something brilliant, otherwise we can only come to the conclusion that the company needs a radical change of direction, for example by developing a new architecture based on AMCC's PowerPC I/O processors.
The LSI MegaRAID SATA 150-4 was labeled a good performer in our previous SATA RAID roundup. The MegaRAID SATA 150-4 and 150-6 have been on the market for almost two years now, and in the meantime the performance of the LSI adapters has been exceeded by new products such as the Areca ARC-1120 and the RAIDCore BC4852. The problem simply is in the out-of-date architecture of the MegaRAID SATA 150. Combining an underpowered I/O processor with slow memory and a bandwidth-limited 32-bit 66MHz PCI bus is the perfect recipe for poor scalability. In many of the workload simulations, there is no performance scaling in RAID 5 configurations consisting of more than four disks. The problem is certainly not within LSI's RAID stack, as we have seen excellent performance from LSI's latest SCSI RAID adapters. In spite of the out-of-date architecture, the MegaRAID SATA 150-4/6 still realized good performance in the database and mailserver scenarios.
More or less the same applies to the Promise FastTrak S150 SX4. A year ago it would have been a nice solution if driver issues wouldn't have spoiled the party. The performance of the FastTrak S150 SX4 has been completely overthrown by the newcomers from Areca, HighPoint and RAIDCore. The SX4's low price per port is no longer an advantage now that the 8-port RocketRAID 1820A can be bought for a price-premium of only 60 euros.
Words of thanks
This review wouldn't have been possible without the cooperation of 3ware, Areca, HighPoint, LSI Logic, WebConneXXion and Western Digital. We would particularly like to thank John Mocnik of WebConneXXion and Dennis Hompes of LVT Benelux PR for providing the RAIDCore BC4852 and the eight Western Digital Raptor WD740GD drives. Lastly, we would like to thank Hans van Zijl and the forum users phYzar, Gondor, MadMarky, Crash_neo, hezik, JoetjeF, tweakerbee, sverzijl, OnTracK, silentsnow, Rafe and F_J_K for helping in translating the original Dutch article.