From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phil Turmel Subject: Re: proactive disk replacement Date: Tue, 21 Mar 2017 13:00:06 -0400 Message-ID: References: <3FA2E00F-B107-4F3C-A9D3-A10CA5F81EC0@allygray.2y.net> <11c21a22-4bbf-7b16-5e64-8932be768c68@websitemanagers.com.au> <58D1244E.3040204@hesbynett.no> <58D1381E.1080101@hesbynett.no> <58D14764.60909@youngman.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <58D14764.60909@youngman.org.uk> Sender: linux-raid-owner@vger.kernel.org To: Wols Lists , David Brown , Gandalf Corvotempesta Cc: Reindl Harald , Jeff Allison , Adam Goryachev , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 03/21/2017 11:31 AM, Wols Lists wrote: > On 21/03/17 14:26, David Brown wrote: >> It is possible that if there are a large number of UREs from a >> drive, that the RAID system will consider the whole drive bad and >> drop it. But other than that, UREs will be treated independently. > > Doesn't mdadm have a setting that does exactly that? Too many UREs > and the drive gets dropped? I'm sure I've come across that > interfering with rebuilds. Yes. MD maintains a per-member-device counter of read errors and drops the device when the counter reaches 20 (twenty). The counter is decremented by 10 (ten) once an hour. A short burst of less than 20 read errors will be tolerated, as long as they don't continue at more than 10/hour. Last I checked, this behavior is hard-coded. Phil