Dependable SCSI RAID Controllers for Linux?

PalmKiller asks: "I have been using DPT (now Adaptec) SmartRaid controllers for years with great results in Linux, but with the advent of the Adaptec assimilation they became more unreliable in current kernels (in the 2.2 or 2.4 tree)...at least for the DPT SmartRaid V and Adaptec branded equivalents, ie: the kernel panics under stress...you know when you try to use it for anything but an idle uptime box. The crashes have something to do with 5 minute long command queues creating havoc in the kernel. I have a few SmartRaid IV controllers that plug away without issue, but they use a different driver. I suspect the programmers and people who knew how to program the Adaptec/DPT controllers got lost in the buyout, or perhaps driver quality control took a dive. I would greatly appreciate other Slashdot readers opinions on a good replacement that is available in the US."

"I have been considering ICP Vortex RZ and RS series and AMI Megaraid as possibles, along with the Mylex line of controllers. I would like some opinions, praises and even nightmare stories on any of these. I am not wanting to invest $350-$1500 per controller on another nightmare like Adaptec/DPT line. It should be obvious but cost is not primary, reliability and to a lesser degree performance are the key issues. In addition I run my controllers in RAID 5 with a hot spare, so suggestions should be for controllers that can do that RAID mode and ones that can be administered from a running Linux system so I can do hot swapping. I would also like controllers whose manufacturer keeps current patches available for the stock kernel tree or is in the kernel tree (for both 2.2 and 2.4, I use 2.2 mostly due to issues with 2.4) as I never use a canned kernel after the install is done. If you run Windows or some other truthfully Adaptec supported OS look for a few *good* DPT or Adaptec controllers on eBay when the swap-out is all over."

Mylex controllers are junk

[krow]

I would blame a really large portion of Slashdot's downtime, and the recent downtime with Freshmeat, on those controllers. Outside of a Megadrive that I used at the Virtual Hospital [vh.org], those are probably some of the worst pieces of Hardware I have ever ran into.
I would never recommend that anyone ever use those cards. Flaky hardware is one issue, but those cards have consistently been the root of a lot of sleepless nights for me fixing the mess that they have caused.

What about ATA RAID 5?

[dschuetz]

Does anyone have any thoughts about IDE raid, especially the offerings from Promise Technology [promise.com]? They've got cards that do RAID 5 with regular IDE drives, including hot failover capability. They've also got subsystems that put a full 8 disks into a RAID array, but presents it to the controller as a single SCSI device.

Advantages: Cheap drives.
Disadvantages: Speed, maybe, though since it's all going directly into the PCI bus, I'm not sure this is an issue.

Anyone used these? Comments? I figure with their SuperTrax controller and a bunch of 80 or 100-G drives, you could have half a terabyte in your basement for under two grand.

Re:SCSI is DEAD

[megabeck42]

Aight, sorry - I do agree with you, and have a stack of IBM DDYS disks to show for it - BUT, you said some things that were wrong:

Just about all PCI ide controllers can use DMA, which cuts the cpu intensiveness down to almost the scsi-level.

Further, Not all drives have to have their own individual interrupt - this depends on the ide chip and how they are arranged on the pci daughterboard, or on the motherboard. (interrupt sharing, etc.) Promise chips will use one interrupt for two interfaces.

SCSI does offer a whole slew of advantages, disconnect, command queueing, etc. These are advantages in a RAID setup. IDE does suck, but not because it's cpu intensive or gobbles interrupts.

Re:What about ATA RAID 5?

[Strog]

The Promise and Highpoint controllers are actually soft-RAID meaning they use the host CPU. 3ware has a good hardware IDE RAID up to 8 drives but they seemed to stop selling them execpt in their sub-systems. Everything I've heard about the Linux drivers is that they are good and I know the FreeBSD drivers are rock-solid. I think the Adaptec controller is hardware too but am not 100% on that.