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 10:00:17 -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 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? > >> In the mean time, do this (or better to set it to 30, for instance): >> >> # Set minimum and maximum raid rebuild speed to 60MB/s. >> echo "Setting minimum and maximum resync speed to 60 MiB/s..." >> echo 60000 > /sys/block/md0/md/sync_speed_min >> echo 60000 > /sys/block/md0/md/sync_speed_max > > sync_speed_max defaults to 200000 on this box already. > 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? > > -- > 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 > You want to use sync_speed_min. Justin.