From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wols Lists Subject: Re: sector size mismatch a problem for RAID 1? Date: Fri, 3 Feb 2017 11:20:17 +0000 Message-ID: <58946771.4030005@youngman.org.uk> References: <3dcb5a7a-9bd4-4cfd-a655-91a88692c549@EXHT01.net.ucsf.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: "Boylan, Ross" , "linux-raid@vger.kernel.org" List-Id: linux-raid.ids On 03/02/17 06:18, Boylan, Ross wrote: > When I moved the new disk to an internal drive bay (after reading lvm-raid wiki's statements that RAID shouldn't be used over a USB link) the problems went away--at least so far. > As I understand it, the problem is that the USB interface goes to sleep. So when you try to write to it, it may not wake up quick enough, causing havoc ... > I wonder if this is the source of my original problem: I was using a single disk RAID1 where the single disk had a USB connection. However, I did get a failure off that drive doing a dd off the raw device. > Quite likely. But I'm puzzled as to why the dd would fail, as this would keep the USB interface active. Maybe others who know more will chime in and explain. > > Ross Cheers, Wol