Date: Mon, 28 Aug 2023 10:56:33 -0700 From: Pete Wright <pete@nomadlogic.org> To: Alexander Motin <mav@FreeBSD.org>, freebsd-current@freebsd.org Subject: Re: zfs autotrim default to off now Message-ID: <ffa25b60-3500-6006-0a35-2b9ffd3b2c2c@nomadlogic.org> In-Reply-To: <de2b9081-4f3b-c19b-b658-08dd9acb563d@FreeBSD.org> References: <cpzqsgncysqm4xwarzue2n6vxpzw2yl4owlcwf64mcgzleclbb@eltdofcwp6iw> <de2b9081-4f3b-c19b-b658-08dd9acb563d@FreeBSD.org>
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On 8/28/23 07:23, Alexander Motin wrote: > Hi Pete, > > On 27.08.2023 23:34, Pete Wright wrote: >> looking at a recent pull of CURRENT i'm noticing this in the git logs: >> >> #15079 set autotrim default to 'off' everywhere >> >> which references this openzfs PR: >> https://github.com/openzfs/zfs/pull/15079 >> >> >> looking at the PR i'm not seeing a reference to a bug report or >> anything, is >> anyone able to point me to a bug report for this. it seems like a >> pretty major >> issue: >> "As it turns out having autotrim default to 'on' on FreeBSD never >> really worked >> due to mess with defines where userland and kernel module were getting >> different >> default values (userland was defaulting to 'off', module was thinking >> it's >> 'on')." >> >> i'd just like to make sure i better understand the issue and can see >> if my >> systems are impacted. > > You are probably misinterpreting the quote. There is nothing wrong with > the autotrim itself, assuming your specific devices properly handle it. > It is just saying that setting it to "on" by default on FreeBSD, that > was done to keep pre-OpenZFS behavior, appeared broken for a while. So > that commit merely confirmed the status quo. It should not affect any > already existing pools. On a new pool creation the default is now > officially "off", matching OpenZFS on other platforms, but there is no > reason why you can not set it to "on", if it is beneficial for your > devices and workloads. As alternative, for example, you may run trim > manually from time to time during any low activity periods. > OK I think that makes sense. So to be clear, if we were using the default autotrim=enabled behavior we in fact weren't having our SSDs trimmed? I think that's my concern, as an admin I was under the impression that it was enabled by default but apparently that wasn't actually happening. -pete -- Pete Wright pete@nomadlogic.org @nomadlogicLA
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