From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Boldi Subject: Re: RAID0 performance question Date: Sun, 27 Nov 2005 20:40:47 +0300 Message-ID: <200511272040.47644.a1426z@gawab.com> References: <437E2CB6.2030903@xss.co.at> <200511271839.16480.a1426z@gawab.com> <001f01c5f36e$9ec7e620$0400a8c0@dcccs> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <001f01c5f36e$9ec7e620$0400a8c0@dcccs> Content-Disposition: inline Sender: linux-raid-owner@vger.kernel.org To: JaniD++ Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids JaniD++ wrote: > Al Boldi wrote: > > Neil Brown wrote: > > > On Saturday November 26, djani22@dynamicweb.hu wrote: > > > > The cat /dev/nb# >/dev/null makes ~ 350 Mbit/s on each nodes. > > > > The cat /dev/nb0 + nb1 + nb2 + nb3 in one time parallel makes > > > > ~780-800 Mbit/s. - i think this is my network bottleneck. > > > > How much do you get w/ nb0+1,2,3 and nb0+1+2,3 respectively? > > I unable to test write, because this is a productive system. > Think this value is about 75-80 per node and ~200-250 in md31. How much do you get with: cat nb# + nb# > /dev/null cat nb# + nb# + nb# > /dev/null respectively? > > > > But the cat /dev/md31 >/dev/null (RAID0, the sum of 4 nodes) only > > > > makes ~450-490 Mbit/s, and i dont know why.... > > > > > > > > Somebody have an idea? :-) > > > > > > Try increasing the read-ahead setting on /dev/md31 using 'blockdev'. > > > network block devices are likely to have latency issues and would > > > benefit from large read-ahead. > > > > Also try larger chunk-size ~4mb. > > Ahh. > This is what i can't do. :-( > I dont know how to backup 8TB! ;-) Maybe you could use your mirror!? -- Al