Date: Tue, 17 Nov 2015 08:32:33 +0000 From: krad <kraduk@gmail.com> To: Miroslav Lachman <000.fbsd@quip.cz> Cc: "Patrick M. Hausen" <hausen@punkt.de>, Freddie Cash <fjwcash@gmail.com>, freebsd-scsi@freebsd.org, freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: ZFS on labelled partitions Message-ID: <CALfReye3vD%2BCumHtPM6GJ2LkGLfC9cFTmsUmodeDgVEHFzz5aA@mail.gmail.com> In-Reply-To: <564AE3E0.9060209@quip.cz> References: <5644FF09.9090200@free.de> <CA%2BE3k93QrUFA3BvhoswkVDXh2bR2aLYG6Z0TOrisVvNL=%2BMZVA@mail.gmail.com> <56472686.5030301@free.de> <20151114143104.GA41119@in-addr.com> <7710CBCC-E68F-4454-9E29-E50ED1C6B511@sarenet.es> <CAN6yY1sH0PnnF_AGwDsA75i_Z6ptOr4J0c_Gqrt%2BRFO6eZsW-Q@mail.gmail.com> <CAOjFWZ4Js65gQZc6rbT9SKg-jZozziTa=JGpJys6HyejdgWP%2Bg@mail.gmail.com> <20151116205734.GM48728@zxy.spb.ru> <CAOjFWZ49A8b6g=mQL3jzJaNX-Lf%2BuDCvmscyB6F4tr7Ax=HMbg@mail.gmail.com> <878D84A9-4553-413B-ACA4-5ABF499F28C1@punkt.de> <564AE3E0.9060209@quip.cz>
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It was a control thing again, if you were using a partition another application could be using the drive on another partition, therefore zfs couldn't guarantee exclusive use of the disk so had to be more careful in the way it operated the drive. I think this meant I went into write through mode like you say. On 17 November 2015 at 08:22, Miroslav Lachman <000.fbsd@quip.cz> wrote: > Patrick M. Hausen wrote on 11/17/2015 09:08: > >> Hi, all, >> >> Am 16.11.2015 um 22:19 schrieb Freddie Cash <fjwcash@gmail.com>: >>> >>> =E2=80=8BYou label the disks as they are added to the system the first = time. >>> That >>> way, you always know where each disk is located, and you only deal with >>> the >>> labels. >>> >> >> we do the same for obvious reasons. But I always wonder about the possib= le >> downsides, because ZFS documentation explicitly states: >> >> ZFS operates on raw devices, so it is possible to create a >> storage pool comprised of logical >> volumes, either software or hardware. This configuration is not >> recommended, as ZFS works >> best when it uses raw physical devices. Using logical volumes >> might sacrifice performance, >> reliability, or both, and should be avoided. >> >> (from http://docs.oracle.com/cd/E19253-01/819-5461/gbcik/index.html) >> >> Can anyone shed some lght on why not using raw devices might sacrifice >> performance or reliability? Or is this just outdated folklore? >> > > It was on Solaris but not on FreeBSD. If you were using partitions on > Solaris the drive cache was disabled (or something like that, I am not 10= 0% > sure) > > Miroslav Lachman > > _______________________________________________ > freebsd-stable@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org"
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