Re: filesystem dead, xfs_repair won't help

From: Avi Kivity <avi@scylladb.com>
To: Eric Sandeen <sandeen@sandeen.net>,
	Christoph Hellwig <hch@infradead.org>
Cc: Emmanuel Florac <eflorac@intellique.com>,
	Brian Foster <bfoster@redhat.com>,
	linux-xfs@vger.kernel.org
Subject: Re: filesystem dead, xfs_repair won't help
Date: Wed, 12 Apr 2017 19:24:12 +0300	[thread overview]
Message-ID: <815d104f-b5c0-472d-6003-89da43c0c297@scylladb.com> (raw)
In-Reply-To: <dc48012a-7255-4435-4230-884ff9445440@sandeen.net>

On 04/12/2017 07:22 PM, Eric Sandeen wrote:
> On 4/12/17 11:20 AM, Christoph Hellwig wrote:
>> On Wed, Apr 12, 2017 at 07:15:40PM +0300, Avi Kivity wrote:
>>> This preserves the ability to do O_DIRECT reads at 512 byte granularity,
>>> yes?
>> No.
>>
>>> We make use of that (it's probably less important on NVMe; still why
>>> waste bandwidth needlessly).
>> In that case it would be the wrong thing for you.
> And it would be really interesting to see if the 512-byte DIOs you
> issue under ext4 might trigger the same problem in the firmware.

We only issue 512-byte reads, writes are always 4096-byte aligned (and 
usually 128k).

The disk that crashed was my /home; it did see some database loads, but 
not much.

>
> (This is all pure speculation, but that's all we've got) ;)
>
> -Eric