Date: Tue, 9 Feb 2016 18:05:25 +0100 From: "Patrick M. Hausen" <hausen@punkt.de> To: Alan Somers <asomers@freebsd.org> Cc: freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: Best practices for ZFS setup for a strictly SSD based system? Message-ID: <C0C949F9-4402-4C74-BCD7-659D657DB2F8@punkt.de> In-Reply-To: <CAOtMX2h8Hh0b7=STpSkV_c68kc0VEM2DTfiT6yFuHxL_%2BF%2BDwg@mail.gmail.com> References: <2D296837-3B06-4E72-B8B0-A33AE6CE48AE@punkt.de> <CAOtMX2h8Hh0b7=STpSkV_c68kc0VEM2DTfiT6yFuHxL_%2BF%2BDwg@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Hi! > Am 09.02.2016 um 17:32 schrieb Alan Somers <asomers@freebsd.org>: > [...] > http://blog.delphix.com/matt/2014/06/06/zfs-stripe-width/ >=20 >>=20 >> * Will e.g. MySQL still profit from residing on a mirror >> instead of a RAIDZ2, even if all disks are SSDs? >=20 > Yes, because a mirrored vdev has as many read IOPs as all of its disks > combined. So a RAID10 of SSDs will have many read IOPs indeed. Ah =E2=80=A6 yes. Now I remember :) > [=E2=80=A6] > Will MySQL access its files in fixed-size records? If so, you can set > the recsize filesystem property accordingly. If not, you should > probably leave recsize at the default. If you profile MySQL's disk > accesses and determine that there is a dominant recordsize, then go > ahead and set ZFS's recsize to the next highest power of two. >=20 > As usual, disable atime. We already knew these. But thanks a lot for the vdev setup hints! So it will be a mirror for OS and DB and a 4+2 raidz2 for the rest of the data. Our MySQL zvols are currently set up like this: DB files: recordsize=3D16k atime=3Doff primarycache=3Dmetadata InnoDB log files: recordsize=3D128k (rest inherited from above) 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=C3=BCrgen Egeling AG Mannheim 108285
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?C0C949F9-4402-4C74-BCD7-659D657DB2F8>