From mboxrd@z Thu Jan 1 00:00:00 1970 From: "JaniD++" Subject: Re: RAID0 performance question Date: Wed, 23 Nov 2005 11:48:10 +0100 Message-ID: <013901c5f01b$6aae7ad0$a700a8c0@dcccs> References: <437E2CB6.2030903@xss.co.at> <200512022253.17282.a1426z@gawab.com> <00fd01c60367$d8d8f5d0$0400a8c0@dcccs> <200512191416.10665.a1426z@gawab.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: Al Boldi Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids ----- Original Message ----- From: "Al Boldi" To: "JaniD++" Cc: Sent: Monday, December 19, 2005 12:16 PM Subject: Re: RAID0 performance question > JaniD++ wrote: > > For me, the performance bottleneck is cleanly about RAID0 layer used > > exactly as "concentrator" to join the 4x2TB to 1x8TB. > > Did you try running RAID0 over nbd directly and found it to be faster? Now i trying the NBD + RAID0 without the middle layer raid1. I wondering, the speed is much more better! If i use dd in the raid0 and the raid1 layer is active, the traffic is 350-400Mbit/s If i use dd in the raid0 and the raid1 layer is inactive, the traffic is 512-620Mbit/s! If i use parallel dd on all NBD devices, the traffic is 650-720Mbit/s. (on my system's current minimal load) I found it very interesting! The kernel never reports timing information about raids in /sys/block/mdX/stat files! I cannot understand... Cheers, Janos