On Mon, Feb 11, 2013 at 2:49 PM, Roy Sigurd Karlsbakk <roy@xxxxxxxxxxxxx> wrote: >> Why would you plug thousands of dollars of SSD into an onboard >> controller? It's probably running off a 1x PCIE shared with every >> other onboard device. An LSI 8x 8 port HBA will run you a few >> hundred(less than 1 SSD) and let you melt your northbridge. At least >> on my Supermicro X8DTL boards I had to add active cooling to it or it >> would overheat and crash at sustained IO. I can hit 2 - 2.5GB a second >> doing large sequential IO with Samsung 840 Pros on a RAID10. > > Those onboard controllers are usually connect to 8x PCIe or similar. Also, those controllers from LSI won't allow TRIM support, which may come in handy… > Be sure to check your motherboard documentation each time though. It turned out his was connected to a 4x DMI 2.0 bus which I had mistaken as a DMI 1.0 even after reading the docs. Thats approximately a 4x PCI. It was still shared with all the other devices on the motherboard including another 4x slot and gigabit ethernet adapters. Also it wasn't a very good SATA controller even. You can get onboards that are decent. I have several builds that come with onboard LSI SAS controllers. Just those are hooked directly to the northbridge on a dedicated 4x PCIE. The LSI RAID doesn't support TRIM, I don't know any hardware controller that does at yet. I just use them as plain HBAs with md for the raid. When I get a kernel with the mdtrim patches TRIM will just magically(hopefully) start working. -- Dave Cundiff System Administrator A2Hosting, Inc http://www.a2hosting.com -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
