Date: Mon, 12 Sep 2011 20:12:15 +0200 From: "K. Macy" <kmacy@freebsd.org> To: Steven Hartland <killing@multiplay.co.uk> Cc: freebsd-fs@freebsd.org Subject: Re: ZFS-lighttpd2-sendfile, too high IO Message-ID: <CAHM0Q_Piojt=Ob%2BsniMpaO9v1j_mBxCrKXFi6yxWktn2tnnSVQ@mail.gmail.com> In-Reply-To: <F959B6B4287E4B7A9C55B34E7A2EDAC9@multiplay.co.uk> References: <freemail.20110912131045.97846.1@xmldata03.freemail.hu> <F959B6B4287E4B7A9C55B34E7A2EDAC9@multiplay.co.uk>
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2011/9/12 Steven Hartland <killing@multiplay.co.uk>: > sendfile doesn't work as you might expect on zfs, its not zero copy due t= o > the use of none buffer pool memory. > > You do get a benefit but it requires double the amount of memory to get i= t > so we've disabled sendfile > under nginx for zfs based hosts for this very reason. In my performance testing, sending from mmaped I/O on ZFS was dramatically faster (> 2x) than sendfile. Cheers > =A0 Regards > =A0 Steve > ----- Original Message ----- From: "Laszlo KAROLYI" <szoftos@freemail.hu> > To: <freebsd-fs@freebsd.org> > Sent: Monday, September 12, 2011 12:10 PM > Subject: ZFS-lighttpd2-sendfile, too high IO > > >> Hello, Recently I installed a FreeBSD with the newest 8.2-STABLE and zfs >> version. I use lighttpd2 and zfs on it, and munin to monitor the outgoin= g >> bandwidth. Zpool version 28, zfs version 5, with the latest kernel. We h= ave >> a big mp3 archive (half hour, 256kbit/s mp3-s) which lighty serves. This >> means full random IO. When I see that the server serves 15mbit/sec, i se= e >> constantly 8-10Mbyte/sec reads on the zfs raidz1 array, which is too muc= h. >> As I could see from truss logs, lighty uses sendfile and writev.My setti= ngs: >> vfs.zfs.l2c_only_size: 15106737664 > > ... > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > This e.mail is private and confidential between Multiplay (UK) Ltd. and t= he > person or entity to whom it is addressed. In the event of misdirection, t= he > recipient is prohibited from using, copying, printing or otherwise > disseminating it or any information contained in it. > In the event of misdirection, illegible or incomplete transmission please > telephone +44 845 868 1337 > or return the E.mail to postmaster@multiplay.co.uk. > > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" >
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