Date: Sun, 27 Jan 2013 14:56:52 -0000 From: "Steven Hartland" <killing@multiplay.co.uk> To: "Vladislav Prodan" <universite@ukr.net> Cc: current@freebsd.org, fs@freebsd.org Subject: Re: Re[2]: AHCI timeout when using ZFS + AIO + NCQ Message-ID: <16B555759C2041ED8185DF478193A59D@multiplay.co.uk> References: <13391.1359029978.3957795939058384896@ffe16.ukr.net> <221B307551154F489452F89E304CA5F7@multiplay.co.uk> <93308.1359297551.14145052969567453184@ffe15.ukr.net>
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----- Original Message -----
From: "Vladislav Prodan" <universite@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.
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
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