Russ Price <rjp_sun <at> fubegra.net> writes: > > > Did you enable AHCI mode on _every_ SATA controller? > > > > I have the exact opposite experience with 2 of your 3 > > types of controllers. > > It wasn't possible to do so, and that also made me think that a real HBA would work better. First off, with the > AMD SB700/SB800 on-board ports, if I set the last two ports to AHCI mode, the BIOS doesn't even see drives > there, and neither does OpenSolaris; the first four ports work fine in AHCI. The JMicron board came up in > AHCI mode; it never, ever presents a BIOS of its own to change configuration. The Silicon Image board (one > from SIIG) doesn't have an AHCI mode in its BIOS.
Ok so the lack of AHCI on the onboard SBxxx ports is very likely what was causing your performance issues. Legacy IDE mode is significantly slower. Sounds like you hit bugs on your motherboard BIOS that prevented you from detecting drives while in AHCI mode... (You are right that SiI3132 doesn't support AHCI, however this is a FIS-based controller with a hardware interface very similar in design to AHCI, so it doese offer great performance out of the box). IMHO the best 2-port PCIe x1 controller is the Marvell 88SE9128, which is AHCI compliant. I like it not because it supports SATA 6.0Gbps, but PCIe 5GT/s. People often believe that a PCIe 2.5GT/s x1 device can do 250MB/s but this is only achievable with a large Max_Payload_Size. In practice MPS is often 128 bytes which limits them to about 60% of the max throughput, or 150MB/s. Given that 2 drives can easily sustain a read throughput of 200-250MB/s, PCIe 5GT/s comes in handy by allowing about 300MB/s with MPS=128 (500MB/s theoretical). -mrb _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
