Date: Sun, 24 Apr 2011 13:21:34 -0300 From: Sergio de Almeida Lenzi <lenzi.sergio@gmail.com> To: freebsd-questions@freebsd.org Subject: Re: ZFS performance strangeness Message-ID: <1303662094.42253.4.camel@z6000.lenzicasa> In-Reply-To: <espd78-2at.ln1@it-betrieb.de> References: <espd78-2at.ln1@it-betrieb.de>
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Em Ter, 2011-04-12 às 13:33 +0200, Lars Wilke escreveu: > Hi, > > There are quite a few threads about ZFS and performance difficulties, > but i did not find anything that really helped :) > Therefor any advice would be highly appreciated. > I started to use ZFS with 8.1R, only tuning i did was setting > > vm.kmem_size_scale="1" > vfs.zfs.arc_max="40000M" For me I solved the ZFS performace in FreeBSD and postgres databases (about 100GB size) by tunning vm.kmem_size to atout 3/4 of the ram size... in your case, vm.kmem_size=(48 *3/4)=36G, it puts almost all the database in memory and it is now lightning fast... I use to disable prefetch in zfs.. too Hope this can help, Sergio
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