Date: Mon, 2 Jun 2014 18:03:26 +0100 From: "Steven Hartland" <killing@multiplay.co.uk> To: "Allan Jude" <allanjude@freebsd.org>, <freebsd-hackers@freebsd.org> Subject: Re: fdisk(8) vs gpart(8), and gnop Message-ID: <EC2C2153C64340E8ACA9DD20EF9D79C5@multiplay.co.uk> References: <20140601004242.GA97224@bewilderbeast.blackhelicopters.org> <CAOjFWZ5N9FGwgSz0_YFNQjavzdJDitRn52VKn4ipW1ddj6-weQ@mail.gmail.com> <BCA9F5D6-3925-4E7E-9082-128652508305@FreeBSD.org> <3D6974D83AE9495E890D9F3CA654FA94@multiplay.co.uk> <538B4CEF.2030801@freebsd.org> <1DB2D63312CE439A96B23EAADFA9436E@multiplay.co.uk> <538B4FD7.4090000@freebsd.org> <538C7035.5080700@freebsd.org>
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----- Original Message ----- From: "Allan Jude" <allanjude@freebsd.org> > On 2014-06-01 12:07, Nathan Whitehorn wrote: >> >> So the discussion here is related to what to do about the installer. The >> current ZFS component unconditionally creates gnops all over the place >> to set ashift to 4k. That's across the board worse: it has exactly the >> performance impact of changing the default of this sysctl (whatever that >> is), it can't easily be overridden (which the sysctl can), and it's a >> horrible hack to boot. There are a few options: >> >> 1. Change the default of vfs.zfs.min_auto_ashift >> 2. Have the same effect but in a vastly worse way by adjusting the >> installer to create gnops >> 3. Have ZFS choose by itself and decide to do that permanently. >> >> Our ATA code is good about reporting block sizes now, so (3) isn't a big >> issue except for the mixed-pool case, which is a huge PITA. >> >> We need to choose one of these. I favor (1). >> -Nathan > > I favour 1 as well. > > Note: the current ZFS installer script forces 4k with gnop if the option > is turned on (it is by default), but you can have it not use gnop. > > But yes, this new sysctl (it is very new), is great. Will it be MFC'd in > time for 9.3? I MFC'ed to stable/10 and stable/9 ~2 weeks so yes :)
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