From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jes Sorensen <jes.sorensen@gmail.com>
Subject: Re: RAID creation resync behaviors
Date: Tue, 9 May 2017 17:22:57 -0400
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To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: NeilBrown <neilb@suse.com>, Shaohua Li <shli@kernel.org>, linux-raid@vger.kernel.org, neilb@suse.de
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On 05/09/2017 05:16 PM, Martin K. Petersen wrote:
> 
> Jes,
> 
>> This is fine within the kernel, however it is not overly useful for
>> mdadm to determine which strategy to apply when syncing devices.
> 
> BLKZEROOUT
> 

Trying to read the code, as this ioctl doesn't seem to be documented 
anywhere I can find.... it looks like this ioctl zeroes out a device.

It doesn't help me obtain the information I need to make a decision in 
mdadm as whether to overwrite all or compare+write when resyncing a RAID 
array.

Jes