Date: Wed, 9 Mar 2011 16:40:51 +0100 From: "Patrick M. Hausen" <hausen@punkt.de> To: Tom Evans <tevans.uk@googlemail.com> Cc: Matthias Andree <matthias.andree@gmx.de>, freebsd-stable@freebsd.org, Jeremy Chadwick <freebsd@jdc.parodius.com> Subject: Re: ZFS performance as the FS fills up? Message-ID: <A18EA020-6A23-4F77-9F32-71FA8D77EE41@punkt.de> In-Reply-To: <AANLkTimMct3Ni0p7CBsmNJmW_t6e75mZcHhQ8dppQbCb@mail.gmail.com> References: <BD2C8439-AC1E-49CB-ABE2-9F7F0B292933@punkt.de> <20110308114810.GA37554@icarus.home.lan> <4D775CF1.1010501@gmx.de> <20110309125132.GB62338@icarus.home.lan> <AANLkTimMct3Ni0p7CBsmNJmW_t6e75mZcHhQ8dppQbCb@mail.gmail.com>
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Hello, Am 09.03.2011 um 14:28 schrieb Tom Evans: > I don't think this is accurate. Prefetch was certainly disabled by > default on 8.0 if you had 4GB of RAM or less, requiring the sysctl > vfs.zfs.prefetch_disable=3D0 to be set if you wanted prefetch and had > 4GB of RAM or less. My configuration is this: JBOD with 24 disks before the performance increase, now 30. 5 vdevs of 6 disks each, raidz2. 16 GB RAM, 8.2 amd64. vm.kmem_size=3D"12288M" vfs.zfs.arc_max=3D"8192M" vfs.zfs.prefetch_disable=3D"1" vfs.zfs.txg.timeout=3D"5" ------- net.inet.tcp.sendbuf_max=3D16777216 net.inet.tcp.recvbuf_max=3D16777216 net.inet.tcp.sendspace=3D65536 net.inet.tcp.recvspace=3D131072 kern.maxvnodes=3D250000 vfs.zfs.txg.write_limit_override=3D1073741824 After I added the last 6 disks net write performance (that means how quick Amanda fills the current vtape) at least doubled. Without any further Amanda tuning. I am aware that there are many components involved that affect performance, so what would be the best way to measure the ZFS part? Working crystal balls have become rare these days ;-) Kind regards, Patrick --=20 punkt.de GmbH * Kaiserallee 13a * 76133 Karlsruhe Tel. 0721 9109 0 * Fax 0721 9109 100 info@punkt.de http://www.punkt.de Gf: J=FCrgen Egeling AG Mannheim 108285
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