From mboxrd@z Thu Jan 1 00:00:00 1970 From: "jonathan@infinitedepth.com.au" Subject: Re: raid5 to raid6 - reshape very slow Date: Tue, 29 May 2012 19:59:37 +1000 Message-ID: <4FC49E09.3090302@infinitedepth.com.au> References: <4FC41970.5080009@infinitedepth.com.au> <20120529105619.4dd15511@notabene.brown> <4FC478FA.2020100@hardwarefreak.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4FC478FA.2020100@hardwarefreak.com> Sender: linux-raid-owner@vger.kernel.org To: stan@hardwarefreak.com, NeilBrown Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids I suspected the only move was to wait it out. Thanks for the feedback Stan & Neil. On 29/05/2012 5:21 PM, Stan Hoeppner wrote: > On 5/28/2012 7:56 PM, NeilBrown wrote: >> On Tue, 29 May 2012 10:33:52 +1000 Jonathan Molyneux >> wrote: >>> md1 : active raid6 sde1[0] sdb1[6] sdh1[5] sdc1[4] sdg1[3] sdd1[2] sdf1[1] >>> 7325679680 blocks super 0.91 level 6, 64k chunk, algorithm 18 >>> [7/6] [UUUUUU_] >>> [=========>...........] reshape = 47.0% (689413888/1465135936) >>> finish=4126.9min speed=3132K/sec >> The only thing to do is to wait. This is very much a seek-bound operation >> and there is little room for making it go faster. > With SSDs you'd see the throughput of this operation increase by 2 > orders of magnitude (100x) or more, as SSDs have application level seek > latency of ~50-80 microseconds, over 100x lower than rotational drives > which are in the 10-30 millisecond range depending on spindle speed. > > Of course, cost/GB for the same total storage is 2 to 10 times higher > with SSD. Though interestingly the price of SSDs continues to fall, > whereas the rotational drive manufacturers are currently keeping drive > prices artificially high, between 50-100% higher than last year > depending on drive model, in an effort to recoup apparent financial > losses caused by the flooding in Thailand. >