From mboxrd@z Thu Jan 1 00:00:00 1970 From: "JaniD++" Subject: Re: RAID0 performance question Date: Wed, 23 Nov 2005 10:44:36 +0100 Message-ID: <007b01c5f012$89bdebd0$a700a8c0@dcccs> References: <437E2CB6.2030903@xss.co.at><200511272040.47644.a1426z@gawab.com><041e01c5f605$6a7c0830$0400a8c0@dcccs><200512022253.17282.a1426z@gawab.com><00fd01c60367$d8d8f5d0$0400a8c0@dcccs><17320.45715.533255.759042@cse.unsw.edu.au><00fd01c5ef07$f41bf690$a700a8c0@dcccs> <17322.12373.766596.426816@cse.unsw.edu.au> 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: Neil Brown Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids ----- Original Message ----- From: "Neil Brown" To: "JaniD++" Cc: Sent: Thursday, December 22, 2005 5:49 AM Subject: Re: RAID0 performance question > On Tuesday November 22, djani22@dynamicweb.hu wrote: > > I have already try the all available options, including readahead in all > > layer (result in earlyer mails), and chunksize. > > But with this settings, i cannot workaround this. > > And the result is incomprehensible for me! > > The raid0 performance is not equal with one component , with sum of all > > component , and not equal with the slowest component! > > This is quite perplexing. > > My next step would probably be to watch the network traffic with > tcpdump or ethereal. I would look for any differences between when it > is going quickly (without raid0) and when slowly (with raid0). > > Rather than tcpdump, it might be easier to instrument the nbd server > to print out requests and timestamps. Yes, it is good idea! I will try it, thanks! > > Sorry I cannot be more helpful, and do have a Merry Christmas anyway > :-) The same to you, and everybody on this list! :-) Cheers, Janos > > NeilBrown > - > 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