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From: Anand Jain <anand.jain@oracle.com>
To: Chris Murphy <lists@colorremedies.com>,
	ronnie sahlberg <ronniesahlberg@gmail.com>
Cc: Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: Re: btrfs fail behavior when a device vanishes
Date: Mon, 11 Jan 2016 17:46:25 +0800	[thread overview]
Message-ID: <569379F1.2060208@oracle.com> (raw)
In-Reply-To: <CAJCQCtQ5Df8p4gJwBDLAF0HgKg9HNiNVbphn9=ao3To8CvkRkQ@mail.gmail.com>


> Already we know that Btrfs tries to write indefinitely to missing
> devices.

(sorry for the late reply, now back from vacation).
The below and its related patch will take care of it, if when
critical IO fails it can bring the device to an offline / failed
state, so that it prevents further IOs to it.

  [PATCH 07/15] btrfs: introduce device dynamic state transition to 
offline or failed

  Further this could provide btrfs sysfs user interface so that
  externally device error monitoring scripts can bring the device
  offline / failed. (we need to settle the sysfs framework and
  patchset to add that sysfs interface).

> If it reappears, what gets written? Will that device be
> consistent?

  Yep that part of the error handling isn't present. The workaround
for it is to use the remount. (sorry if certain setup considers
remount as not suitable). However this kind of the user involved
recovery option is safe from the intermittently failing devices,
which may lead to a messy situation as you mentioned.

Thanks, Anand

      parent reply	other threads:[~2016-01-11  9:46 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-31 20:11 btrfs fail behavior when a device vanishes Chris Murphy
2015-12-31 20:17 ` Chris Murphy
2015-12-31 20:24 ` Hugo Mills
2015-12-31 20:43   ` Chris Murphy
2015-12-31 21:23 ` ronnie sahlberg
2016-01-01  1:09   ` ronnie sahlberg
2016-01-01  1:27     ` Chris Murphy
2016-01-01  1:37       ` ronnie sahlberg
2016-01-01  1:45       ` ronnie sahlberg
2016-01-11  9:46       ` Anand Jain [this message]

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