From mboxrd@z Thu Jan 1 00:00:00 1970 From: Goswin von Brederlow Subject: Odd raid5 reshape behaviour Date: Wed, 25 Nov 2009 11:09:23 +0100 Message-ID: <874ooiq5kc.fsf@frosties.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid List-Id: linux-raid.ids Hi, I'm reshaping a raid5 from 3 to 4 disks and I'm seeing something odd. md2 : active raid5 sda3[3] sdd3[2] sdc3[1] sdb3[0] 2832114688 blocks super 0.91 level 5, 64k chunk, algorithm 2 [4/4] [UUUU] [==============>......] reshape = 73.2% (1037811200/1416057344) finish=276.4min speed=22802K/sec Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn sda3 792.90 0.00 27459.20 0 274592 sdb3 433.70 0.00 27459.20 0 274592 sdc3 393.20 0.00 27459.20 0 274592 sdd3 399.10 0.00 27458.80 0 274588 The reshape has copied all the old stripes to new positions and now I guess it fills the drives with zeroes for the remainder. But why are they roughly twice as many tps on sda, which is the new disk? All drives write the same amount of data but sda seems to write it in twice as many chunks. MfG Goswin