From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Mamedov Subject: Re: strange mirror write perf Date: Mon, 20 Mar 2017 10:07:42 +0500 Message-ID: <20170320100742.712ebe4d@natsu> References: <6ec5f2dbefa2b7489d9f39d4833d5113@grim-is-a-geek.fr> <3a5e061d-696d-f331-87a5-411edc514ada@websitemanagers.com.au> <91d1857a35f0c659387a409cc147ac92@grim-is-a-geek.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <91d1857a35f0c659387a409cc147ac92@grim-is-a-geek.fr> Sender: linux-raid-owner@vger.kernel.org To: Youenn Gestin Cc: Adam Goryachev , linux-raid@vger.kernel.org List-Id: linux-raid.ids On Mon, 20 Mar 2017 01:44:09 +0100 Youenn Gestin wrote: > abyss ~ # dd bs=1M count=2024 if=/dev/zero of=/dev/md/md6to > conv=fdatasync > 2024+0 records in > 2024+0 records out > 2122317824 bytes (2,1 GB, 2,0 GiB) copied, 14,5074 s, 146 MB/s > > I'll check about this function to see if i'll need it or not tomorow, Instead of disabling it you can alter the bitmap chunk size, and at larger chunk sizes it does not affect the performance as much. http://tgharold.blogspot.fr/2013/01/mdadm-using-bitmaps-to-speed-up-rebuilds.html For 6TB drives try 256 or even 512MB for the size. -- With respect, Roman