From mboxrd@z Thu Jan 1 00:00:00 1970 From: Justin Piszcz Subject: Re: AWFUL reshape speed with raid5. Date: Mon, 28 Jul 2008 14:14:21 -0400 (EDT) Message-ID: References: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Jon Nelson Cc: LinuxRaid List-Id: linux-raid.ids What happens if you use 0.90 superblocks? Also, are these sata ports on the mobo or sata ports on a pci-based mobo? On Mon, 28 Jul 2008, Jon Nelson wrote: > I built a raid5 with 2 devices (and --assume-clean) using 2x 4GB > partitions (not logical volumes). > I then grew it to 3 devices. > The reshape speed is really really slow. > > vmstat shows I/O like this: > > 0 0 212 25844 141160 497484 0 0 0 612 673 1284 0 6 93 0 > 0 0 212 25164 141160 497748 0 0 0 19 594 1253 1 4 95 0 > 0 0 212 25044 141160 498004 0 0 0 0 374 445 0 1 99 0 > 1 0 212 25220 141164 498000 0 0 0 23 506 1149 0 3 96 1 > 0 0 212 25500 141164 498004 0 0 0 3 546 1416 0 5 95 0 > > The min/max is 1000/200000. > What might be going on here? > > Kernel is 2.6.25.11 (openSUSE 11.0 x86-64 stock) > > /proc/mdstat for this entry: > > md99 : active raid5 sdd3[2] sdc3[1] sdb3[0] > 3903744 blocks super 1.0 level 5, 64k chunk, algorithm 2 [3/3] [UUU] > [=>...................] reshape = 8.2% (324224/3903744) > finish=43.3min speed=1373K/sec > > > This is on a set of devices capable of 70+ MB/s. > > No meaningful change if I start with 3 disks and grow to 4, with or > without bitmap. > > -- > Jon > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >