From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adam Goryachev Subject: Re: Uneven wear on raid1 devices Date: Wed, 27 Jan 2016 11:18:44 +1100 Message-ID: <56A80CE4.1090603@websitemanagers.com.au> References: <56A5B29E.3020708@websitemanagers.com.au> <20160125104027.597041a3@natsu> <56A662A3.6000402@turmel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <56A662A3.6000402@turmel.org> Sender: linux-raid-owner@vger.kernel.org To: Phil Turmel , Roman Mamedov Cc: linux-raid List-Id: linux-raid.ids On 26/01/16 05:00, Phil Turmel wrote: > On 01/25/2016 12:40 AM, Roman Mamedov wrote: >> On Mon, 25 Jan 2016 16:29:02 +1100 >> Adam Goryachev wrote: >> >>> 9 Power_On_Hours -O--CK 098 098 000 - 6435 >>> 9 Power_On_Hours -O--CK 095 095 000 - 23178 >> 2nd drive has almost 4x as much power-on time than the first one. My guess >> would be that it accumulated all that write usage back before you put it into >> this RAID1. > Or you are doing "repair" scrubs when you should be doing "check" > scrubs. Any operation that requires resynchronization will read from > the first mirror and write to the others. No, definitely not doing a repair scrub, so sounds like the issue was just the power on hours problem. >> If you want to ensure the RAID1 usage is even, record the SMART data you have >> now, and compare to the readings you will have a month later. > By the way, your devices show scterc disabled. That's bad. You should > definitely use boot scripts or udev rules to enable it. Ooops, thank you for catching this, well understood how bad it is, I just assumed (badly) that I was using decent drives (I always used the WD enterprise black), and clearly forgot to check for this on an SSD. I've enabled it now from /etc/rc.local, as well as fixing the scheduler to noop on the SSD instead of cfq. > Has sdd been getting bumped out of the array lately, and resyncing when > you put it back? No, but I wonder if this might have explained the drop from around 9 months ago, when I re-plugged it and it tested fine, but I asked them to replace it anyway (which they did). So, I can't complain about it too much. Regards, Adam -- Adam Goryachev Website Managers www.websitemanagers.com.au