Date: Sat, 6 Jul 2013 08:10:29 +0300 From: Daniel Kalchev <daniel@digsys.bg> To: Jeremy Chadwick <jdc@koitsu.org> Cc: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org> Subject: Re: Slow resilvering with mirrored ZIL Message-ID: <209EBC4A-45C6-4F94-87C3-9679B8A0691E@digsys.bg> In-Reply-To: <20130705145332.GA5449@icarus.home.lan> References: <CBCA1716-A3EC-4E3B-AE0A-3C8028F6AACF@alumni.chalmers.se> <20130704000405.GA75529@icarus.home.lan> <C8C696C0-2963-4868-8BB8-6987B47C3460@alumni.chalmers.se> <20130704171637.GA94539@icarus.home.lan> <2A261BEA-4452-4F6A-8EFB-90A54D79CBB9@alumni.chalmers.se> <20130704191203.GA95642@icarus.home.lan> <43015E9015084CA6BAC6978F39D22E8B@multiplay.co.uk> <CAOjFWZ4obK1cSmvTpW%2Bt4xKdMf%2BkJV5w-sujDT1AZoepj%2B5YrA@mail.gmail.com> <3CFB4564D8EB4A6A9BCE2AFCC5B6E400@multiplay.co.uk> <51D6A206.2020303@digsys.bg> <20130705145332.GA5449@icarus.home.lan>
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On 05.07.2013, at 17:53, Jeremy Chadwick <jdc@koitsu.org> wrote: > On Fri, Jul 05, 2013 at 01:37:58PM +0300, Daniel Kalchev wrote: >>=20 >> On 05.07.13 02:28, Steven Hartland wrote: >>>=20 >>>=20 >>> If anyone wants my current patches which add switch to 4k ashift >>> by default >>> as a sysctl + works with QUIRKS too, just let me know. >>>=20 >>> They are well tested, just we want more options before putting in >>> the tree. >>=20 >> Is it not easier to add this as an option to zpool create, instead >> of an sysctl? >>=20 >> That is, I believe we have two scenarios here: >>=20 >> 1. Having an sysctl that instructs ZFS to look at the FreeBSD quirks >> to decide what the ashift should be, instead of only querying the >> 'sectorsize' property of the storage. I believe we might not even >> need an sysctl here, just make it default to obey the quirks --- but >> sysctl for the interim period will not hurt (with the proper >> default). >=20 > I can expand on this one (specifically "relying on sectorsize of the > media"): no, this will not work reliably, for two reasons. =20 This is how ZFS works now. While I am we'll aware that most people use disk= s with all the quirks manufacturers put there, lets not forget ZFS was desig= ned for the enterprise environment, where "storage device" has much wider me= aning and "sector size" also varies wildly. Having said this and because FreeBSD actually goes via geom for disks now, f= iguring out the correct "sector size" is for geom to do. As it is now, perha= ps ZFS should be made to query the "stripe size" property of the geom provid= er and not the "sector size". A sysctl to that effect makes more sense to me= , will make things more automatic for most users. Daniel=
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