Revisions:
Originally published December 22 2006.
Summary:
The Dell CERC SATA 1.5/6ch RAID controller is a rebranded Adaptec card, available on Dell's PowerEdge 1800+ and NAS units. Dell sold OEM solutions with this card, coupling it with 250GB or larger drives, touting a 1TB or larger storage solution in 4U.
The problem is, the card performs horribly, compared to other competing solutions. This card is a poor representation of what SATA is capable of doing. Avoid this card if you can.
Dell never officially made claims about the performance of this hardware, but providing it as an option, and refusing to publish benchmarks or performance data means that a lot of people have this card in production - and hate it.
If you need a SATA hardware RAID card for a file server, web server... get a 3Ware 9650SE card.
Details:
As Dell doesn't provide a BBU option with this card, I used this with the write cache disabled. I had 3x320GB WD RE SATA 7200RPM drives in RAID5, and 2x120 WD SATA drives in RAID 1, attached.
I got around 40 MB/sec read and ~3 MB/s write with this card, on my RAID 5 set. This is abysmal, considering its marketed as a "hardware RAID solution". Updated the card firmware, as well as the server BIOS. No use.
Contacting Dell was no help. They scolded me for using a PE1800 with SATA disks; their SCSI solution was clearly the way to go. At a premium of $2000 or more, it ought to be...
I made some changes in the BIOS, and discovered that if I disabled the onboard CERC2S SATA, and onboard LSI SCSI controller, I was able to get much better performance - around 40 MB read/write.
Characterizing the Poor performance:
I never spent the time to run benchmarks with this card. Although I may have a chance in the future, now that I've FINALLY been able to get this card out of service.
However, I have rebuilt the RAID5 set on this card numerous times;
3xWD3200SD (RE, 8 MB cache, 7200RPM, SATA 1.5 Gbps, no NCQ), stripe size 64 kb. Full rebuild with NO load on the drives took 82 hours. EIGHTY-TWO HOURS.
Frustrated with the poor performance, I then added a 4th disk, so I had 4xWD3200SD plugged into a 3Ware 9650SE card. Same 64 kb stipe.
With load on the disks, a rebuild to 42% completion took 3.23 hours. The full rebuild around 7.5 hours.
Comparing just rebuild times, difference is night and day. If I ever had a drive fail on the Dell CERC, I'd likely have another drive fail before the array even finished rebuilding.
I was scolded for having purchased a CERC 1.5/6ch SATA array for such a purpose. The ONLY specifications that Dell had published on the array that they were able to give me over the phone was, "It uses an Intel processor for hardware RAID."
Conclusion:
I have a SATA "RAID" card that performs horribly. While this card is perhaps a nice way to add 6 SATA ports to a system, the cost ($349 with cost of system) is quite hefty. The 3Ware 9650SE 8 port comes in a $591 retail, but the performance difference, driver support, and management utilities are lightyears ahead.