From mboxrd@z Thu Jan 1 00:00:00 1970 From: Justin Piszcz Subject: Re: stripe_cache_size and performance Date: Tue, 26 Jun 2007 11:54:24 -0400 (EDT) Message-ID: References: <5d96567b0706211242p7f03bd1cw9102ae3e44d67cee@mail.gmail.com> 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To: Jon Nelson Cc: Linux RAID Mailing List List-Id: linux-raid.ids I repeat: what does the patch do (or is this no longer applicable)? This was for if your stripe_cache_size was above a certain number, it would run at 1-3MB/s rebuild speed. You can always force with the min parameter. Forcing it you should get good speed, faster than 1-3MB/s anyway :) Justin. On Tue, 26 Jun 2007, Jon Nelson wrote: > On Tue, 26 Jun 2007, Justin Piszcz wrote: > >> >> >> On Tue, 26 Jun 2007, Jon Nelson wrote: >> >>> On Tue, 26 Jun 2007, Justin Piszcz wrote: >>> >>>> >>>> >>>> On Tue, 26 Jun 2007, Jon Nelson wrote: >>>> >>>>> On Mon, 25 Jun 2007, Justin Piszcz wrote: >>>>> >>>>>> Neil has a patch for the bad speed. >>>>> >>>>> What does the patch do? > > I repeat: what does the patch do (or is this no longer applicable)? > > >>>>> sync_speed_max defaults to 200000 on this box already. > > Altering sync_speed_min... > >>>>> I tried a binary search of values between the default (1000) >>>>> and 60000 which resulted in some pretty weird behavior: >>>>> >>>>> at values below 26000 the rate (also confirmed via dstat output) stayed >>>>> low. 2-3MB/s. At 26000 and up, the value jumped more or less instantly >>>>> to 70-74MB/s. What makes 26000 special? If I set the value to 20000 why >>>>> do I still get 2-3MB/s actual? > >> Sounds quite strange, what chunk size are you using for your RAID? > > The default: 64 > > md0 : active raid5 sdc4[2] sda4[0] sdb4[1] > 613409664 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU] > > > -- > Jon Nelson > - > 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 >