At least as important as hard performance figures are the actual user experiences. Real problems only come to light in the real world, for example poor compatibility with certain motherboards, hard disks which are dropped from the array under certain circumstances, rebuilds which are halfway interrupted or drivers causing very high processor usage. The issues with the drivers of the Promise FastTrak S150 SX4 are perhaps the best example of a RAID adapter that should be performing very well (at last-year standards) according the benchmarks, but was almost unusable in the real world. Fortunately, the problems with this adapter have been solved in the meantime.
Our experiences the adapters in this comparison and our Opteron testbed were generally positive. We had some problems with the HighPoint RocketRAID 1820A, which had to be shipped twice from Taiwan. The first sample failed to recognize any harddisks. Some frustration was caused by the locking feature of the 3ware Escalade 9500S-8 (see page seven for details). The RAIDCore BC4852 lost a hard disk during the RAID 10 test, causing the benchmark application to get stuck in an infinite loop. The problem was solved by rebooting the system. Afterwards the array proved to be degraded. Not very nice: the process should not have been interrupted. After shutting down and restarting the system the disk was there again. A hot reset didn't help. The RAIDCore BC4852 was noted by its quick response to the unplugging of harddisks. Rebuilding the array to the hotspare started immediately after a drive failure. The RocketRAID 1820A performed a similar quick response to the unplugging of disk drives. It's a pity however, that the array disappears when it's created in the management tool and Windows is rebooted during build process. The 3ware Escalade 9500S-8 was very slow at recognising failed drives. Only when I/O activity took place it would detect the drive failure.
Because of its good performance, the Areca ARC-1120 immediately moved to the workstation of yours truly, replacing the LSI MegaRAID SCSI 320-2X with 512MB cache. In the three months which have gone by since then, the ARC-1120 has left a flawless impression. The performance with four WD740GDs in RAID 10 is excellent, at least as good as six Atlas 15Ks in RAID 5 on the MegaRAID SCSI 320-2X. Reliability is higher however, because the SCSI disks tended to fail once in a while. The failures possibly had something to do with overheating of the passively cooled I/O processor on the 320-2X. Systems that have not been built for minimal sound production, shouldn't have any of these overheating issues. The Areca ARC-1120 also reacted very smoothly to the disconnection of hard disks.
The LSI MegaRAID SATA 150-4/6 and the Promise FastTrak S150 SX4 (using the latest drivers and firmware) worked flawlessly in our test system.
Third party experiences
On the forums of Tweakers.net, Storage Review, 2CPU.com and AnandTech we find many user experiences. Users of the 3ware Escalade 8506-8 and Escalade 9500S-8 are generally satisfied with this product, although some users complain about disappointing results in STR benchmarks. We already know that the Escalade 9500S-8 has some problems with the ATTO disk benchmark. This is no indication for real world performance, however. Both cards deliver moderate to poor performance in our RAID 5 benchmarks, but the performance level is usually better than a single SATA disk. This can be an explanation why many people are satisfied about the performance of their 3ware adapters, even though the Escalade adapters perform rather disappointing compared to competetive offerings. 3ware's Linux support is praised everywhere and is a reason why these adapters are frequently used in servers. Certain production series of the Escalade 8506 have had problems with PCI bus signaling in motherboards having 64-bit 66MHz slots. This problem has been solved in new revisions of the Escalade 8506. On SR's forum we can find a report from a user who experiences crashes on his system using a Escalade 9500S plugged into a Tyan Thunder K8S dual Opteron mainboard (the same motherboard as used in our test system, where the Escalade 9500S-8 worked flawlessly). The problem disappeared after replacing the RAID adapter with a RAIDCore BC4852.
User experiences with the Areca ARC-1120 and its 4-, 12- and 16-port familiy members are still scarce. Before the arrival of the PCI SATA RAID adapters, Areca's products were hard to find in Europe. Our preview of the ARC-1120, published in September of 2004, was the reason RAID adapter supplier WebConneXXion decided to bring the Areca SATA RAID adapters to Europe. Several users of our forum are now in possession of an Areca-controller and generally, they seem to be pleased. One user writes about the failure of a disk during online capacity expansion. This was solved by adding a hotspare after the expansion of the array had been completed. On the international forums we have observed hoge interest in the Areca products. The small number of users who have been able to get their hands on an Areca adapter seem to have positive experiences.
HighPoint has been under heavy fire concerning problems with the RocketRAID 1820, ranging from very bad STR benchmarks to stuck mouse cursors and high CPU usage. The users of the RocketRAID 1820A are less prominently present on the forums, possibly a sign that there are fewer problems with the A-variant. The users who have shared their experiences are positive about the performance of the device. There are no reports of serieos performance degradation or slow response to user input from users of the RocketRAID 1820A. The RocketRAID 1820A is especially popular amongst cost-conscious buyers. They consider the lack of online capacity expansion as one of the the largest disadvantages of RocketRAID 1820A. Many home users want to start with a small number of hard disks and increase this number in the future. Online capacity expansion is a very handy feature, although it is always wise to make backups of the data on the array prior to capacity expansion.
The LSI MegaRAID SATA 150-4 and 150-6 have been on the market for quite some time. As evident in our low-level benchmarks, the sequential transfer rates of the MegaRAID SATA 150 adapter are nothing to brag about. As expected, some users complain about poor transfer rates in STR benchmarks. On our forums one report is found of a compatibility problem with an Intel dual Xeon Grand Prairie mainboard, which is remarkable because the LSI MegaRAID SATA 150-6 is also sold by Intel as the SRCU16. Compatibility with Intel mainboards is not something you would expect from an Intel SATA RAID adapter. This user solved his problem by replacing the MegaRAID with a 3ware Escalade 9500S-8. His experience with LSI's support was still positive, there was a quick response time and the treatment of the customer was more personal than at 3ware. There are more known cases of users who had to return their MegaRAID SATA 150-4 or 150-6 to the manufacturer. On the forum someone complains about Maxtor DiamondMax 10 disks not working on the MegaRAID SATA 150-4. We've heard stories about DiamondMax 10 compatibility issues affecting other SATA controllers as well.
We can write whole stories about the problems with the Promise FastTrak S150 SX4. The original FastTrak S150 SX4 driver and firmware showed an indescribable inertia when Windows was booted from an array on the FastTrak S150 SX4. By inertia we mean an almost complete lack of response to user input. This frequently changed between normal speed at one moment and a terrible slowdown at other moments. Furthermore, there are reports of boot problems when the SX4 was used in combination with an onboard Promise-controller, some hard disks where not recognized at boot-time and in some cases, even keyboards were failing due to the FastTrak S150 SX4. The new drivers and firmware, released almost a full year after the introduction of the FastTrak S150 SX4, have fixed most of the issues, so now the FastTrak S150 SX4 can finally be of meaningful use. Unfortunately, the adapter has lost much of its charm in the meantime. Compared to the 2003-generation SATA RAID adapters, the FastTrak S150 SX4 offered respectable performance. Compared to the latest products from the competition, the SX4 is no more than a moderately to badly performing contender. Due to a bad experiences with hard disks failing spontaneously, we still have our doubts about the reliability of the Promise FastTrak S150 SX4.
The RAIDCore BC4852 is the successor to the ill fated RC4852, which was pulled from the market due to reliability problems on certain disks. User reports on the BC4852 are almost unanimously positive. There is one report from a user who couldn't get his Hitachi Deskstar 7K400 drives to work on the BC4852.