X-Recipient: archive-cygwin AT delorie DOT com DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:mime-version:in-reply-to:references:date :message-id:subject:from:to:content-type; q=dns; s=default; b=xP wabOET8v0QXkKNnUqrepNYfvw1rwY10QCGvk7LaVyzo1AQBFuDn6mb289uX/U4OA lOxYxymqVH6YhAyVKIlx6y0Qrl2Wxb7xmWb4rYfspSSGot/Mu5CLp/QNZifwJcZO ura7gYEJskmtfIoALn/BuAojqb/JLN/AdVUoafSF8= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:mime-version:in-reply-to:references:date :message-id:subject:from:to:content-type; s=default; bh=zlQlZ2/n FPMogwrPV+x17dDFNFo=; b=rlXutbx4dxnVoZ369AstsQGgKKMoRLuLMjtynP4b 36sNQrv6WbiDs/XHoToyljcVGxp4CB3/tY569L6tiJXTZFMwSXT1puGOdYGbujKw sngBRcvg3Ehm8MVrn0LfH+R/bOenaPnT6vw9dw0qTO+5t0OMZk2uW38itGlN9NwT h5c= Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=Obviously, reads, 10m, Hx-languages-length:1578 X-HELO: mail-lb0-f180.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:date :message-id:subject:from:to; bh=8J324+Ip7s5G30y8Xzs293TwxoCHYXwRwTYVamlBUjk=; b=bgpETcpgSSVk6Gfcw3mJ194npM1jTVCSvabL321eqNQ/VPPzchSmUI1xyD9+tnlQro 9Tr1rWtn1uspT/1/2DHZjTsguyoax/TvlUrsHM3Pin+kIfqgGmbDTJ0TYPqfJ4vnSCRV gSwjcjy5gBdi9vnBVHFQcTXt8FWI/dSqrmw6g+2GTp6c97GbTtpHGsRQgWPNBne6yWNp cE86TY1a1C53P5i8Tg8RMEUwHj6FmO7WmWIidsYs91Sc40+kDIPv13PwGfVtTGwm45xN 3v0VlSGuZhZs2QOXMCFuDzqaCcn3AC25/HnXZtypnzfoHBVmL3p8f6cvu1SkTmAs95JP wYoA== X-Gm-Message-State: AD7BkJIs9s1SJJ3+IPCK7vfDfZwu1zTvePw2V7P5MUdgSD3I19nIOS0iJoLhDIUsja4CiPkDqYKX8kmES579qQ== MIME-Version: 1.0 X-Received: by 10.112.126.1 with SMTP id mu1mr3425062lbb.70.1458595662484; Mon, 21 Mar 2016 14:27:42 -0700 (PDT) In-Reply-To: References: <0D835E9B9CD07F40A48423F80D3B5A702EAE633E AT USA7109MB022 DOT na DOT xerox DOT net> Date: Mon, 21 Mar 2016 17:27:42 -0400 Message-ID: Subject: Re: cksum giving inconsistent results on network drive From: Erik Soderquist To: cygwin AT cygwin DOT com Content-Type: text/plain; charset=UTF-8 X-IsSubscribed: yes On Mon, Mar 21, 2016 at 5:09 PM, Nem W Schlecht wrote: > On Mon, Mar 21, 2016 at 3:49 PM, Erik Soderquist >> I expect if you did a capture of the traffic, you'd find the traffic >> itself has inconsistent data... > > If the traffic was bad, I'd suspect the byte count to be off as well, > but if the byte count is consistent (which it is here), then the > checksums should all be the same. One random bit flipped in a stream of over 6.6M bits (not counting overhead) would not change the byte count unless that bit happened to be in the file description data rather than the file data (statistically unlikely), but would affect the cksum results. To date, I've never seen the byte count off when I had network problems corrupting files on SMB or NFS (outside of complete connection loss), but I've certainly had corrupt reads and writes of the actual file data. In the presented sampling, 6 out of 11 cksum results are consistent, indicating that the average failure rate is slightly better than 1 in 10M bits. > Have you tried a different hashing program, like md5sum or shasum, to > see if you still get inconsistent results? I would also be interested in these results, as it would focus or rule out cksum as a potential culprit. (Obviously from my previous post, I have my suspicions already, but confirmation is still the best approach). I would also be interested in if you can do the same cksum/md5sum/shasum on the server side and use some kind of semaphore to trigger the check and get the results. -- Erik -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple