Date: Wed, 31 Dec 2008 09:06:26 +0100 From: Peter Boosten <peter@boosten.org> To: Bernard Dugas <bernard@dugas-family.org> Cc: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>, "freebsd-questions@freebsd.org" <freebsd-questions@freebsd.org>, Vincent Hoffman <vince@unsane.co.uk> Subject: Re: Optimising NFS for system files Message-ID: <B07985F1-A9B7-4F5F-AD44-1E971681199F@boosten.org> In-Reply-To: <495B2516.4020904@dugas-family.org> References: <20081216094719.EDCEE1065675@hub.freebsd.org> <495930E4.1030501@dugas-family.org> <20081229230115.F68805@wojtek.tensor.gdynia.pl> <4959DFEF.5090407@dugas-family.org> <20081230150507.U87347@wojtek.tensor.gdynia.pl> <495A3957.9050002@dugas-family.org> <495A3C72.5070802@unsane.co.uk> <20081230201351.L12391@wojtek.tensor.gdynia.pl> <495A9595.6080201@dugas-family.org> <20081231002557.D45571@wojtek.tensor.gdynia.pl> <495B2516.4020904@dugas-family.org>
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On 31 dec 2008, at 08:53, Bernard Dugas <bernard@dugas-family.org> wrote: > Wojciech Puchar wrote: > >>> nfsserver# time tar -cf - clientusr-amd64 > /dev/null >>> 5.001u 12.147s 1:23.92 20.4% 69+1369k 163345+0io 0pf+0w >>> >>> client9# time tar -cf - /usr > /dev/null >>> tar: Removing leading '/' from member names >>> 3.985u 19.779s 4:32.47 8.7% 74+1457k 0+0io 0pf+0w >>> >>> Note : clientusr-amd64 is around 1.3GB and is the same directory >>> exported to client9 /usr with nfs. >>> >> it's FAST. what's wrong? > > First thing that may be wrong is the understanding of the time > figures. The documentation is not clear about them and the -h option > is not working : > > client6# time -h tar -cf - /usr > /dev/null > -h: Command not found. > 0.000u 0.000s 0:00.00 0.0% 0+0k 0+0io 0pf+0w > > The main thing is that the 3rd figures 1:23.92 and 4:32.47 seems to > be the time i wait in front of the computer while it works (ok, i > know, i should enjoy a beer, or hot coffee with this nice snow ;-) : > > client9# date ; time tar -cf - /usr > /dev/null ; date ; > Wed Dec 31 08:23:59 CET 2008 > tar: Removing leading '/' from member names > 4.103u 19.651s 4:25.80 8.9% 74+1453k 0+0io 2pf+0w > Wed Dec 31 08:28:25 CET 2008 > > and 08:28:25 - 08:23:59 = 00:04:26 is very close to 4:25.80. > > On server, it means : 1440MB / 84s = 17MB/s > On client, that becomes : 1440MB / 266s = 5.4MB/s > > I know the disk is not very fast, but i would like the NFS layer not > to add too much... > > I don't want my users to wait between 3 or 4 times more because > computer is using NFS. In my opinion there are more considerations than only nfs: the data is pulled twice over the network, and the tar process might initiate paging which is done over the network as well. The tar comparison is not a good one. Peter -- http://www.boosten.org
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