Re: trying to balance, filesystem keeps going read-only.

[Roman Mamedov <rm@romanrm.net>]

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On Sun, 1 Nov 2015 09:07:08 -0500
Ken Long <kelargo1000@gmail.com> wrote:

> Yes, the one drive is that Seagate 8TB drive..
> 
> Smart tools doesn't show anything outrageous or obvious in hardware.
> 
> Is there any other info I can provide to isolate, troubleshoot further?
> 
> I'm not sure how to correlate the dmesg message to a specific drive,
> SATA cable etc..

See this discussion: http://www.spinics.net/lists/linux-btrfs/msg48054.html

My guess is these drives need to do a lot of housekeeping internally,
especially during heavy write load or random writes, and do not reply to the
host machine in time, which translates into those "frozen [...] failed
command: WRITE FPDMA QUEUED" failures.

I did not follow the issue closely enough to know if there's a solution yet, or
even if this is specific to Btrfs or to GNU/Linux in general. Maybe your best
bet would be to avoid using that drive in your Btrfs array altogether for the
time being.

-- 
With respect,
Roman

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