Re[2]: Re[2]: AHCI timeout when using ZFS + AIO + NCQ

From: Vladislav Prodan <universite_at_ukr.net>
Date: Sun, 27 Jan 2013 17:13:25 +0200
('binary' encoding is not supported, stored as-is) > ----- Original Message ----- > From: "Vladislav Prodan" <universite_at_ukr.net> > > >> Is it always the same disk, of so replace it SMART helps identify issues > >> but doesn't tell you 100% there's no problem. > > > > > > Now it has fallen off a different HDD - ada0. > > I'm 99% sure that MHDD will not find problems in HDD - ada0 and ada2. > > I still have three servers with similar chipsets that have similar problems > > with blade ahci times out. > > I notice your disks are connecting at SATA 3.x, which rings bells. We had > a very similar issue on a new Supermicro machine here and after much > testing we proved to our satisfaction that the problem was the HW. I have a motherboard ASUS M5A97 PRO http://www.asus.com/Motherboard/M5A97_PRO/#specifications Has replacement SATA data cables. Putting hard RAID controller does not guarantee data recovery at his death. > Essentially the combination of SATA 3 speeds the midplane / backplane > degraded the connection between the MB and HDD enough to cause > the disks to randomly drop when under load. > > If we connected the disks directly to the MB with SATA cables the > problem went away. In the end we had midplanes changed from an > AHCI pass-through to active LSI controller. > > So if you have any sort of midplane / backplane connecting your disks > try connecting them direct to the MB / controller via known SATA 3.x > compliant cables and see if that stops the drops. > > Another test you can do is to force the disks to connect at SATA 2.x > this also fixed it in our case, but wasn't something we wanted to > put into production hence the controller swap. > > To force SATA 2 speeds you can use the following in /boot/loader.conf > where 'X' is disk identifier e.g. for ada0 X = 0:- > hint.ahcich.X.sata_rev=2 > > Hope this helps. > > Regards > Steve > -- Vladislav V. Prodan System & Network Administrator http://support.od.ua +380 67 4584408, +380 99 4060508 VVP88-RIPE Received on Sun Jan 27 2013 - 14:29:05 UTC

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