Date: Fri, 17 Jan 2020 14:21:51 +0300 From: Slawa Olhovchenkov <slw@zxy.spb.ru> To: Eugene Grosbein <eugen@grosbein.net> Cc: Ed Maste <emaste@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, Oliver Pinter <oliver.pntr@gmail.com>, Nathan Whitehorn <nwhitehorn@freebsd.org>, Ben Woods <woodsb02@freebsd.org>, Warner Losh <imp@bsdimp.com> Subject: Re: svn commit: r356758 - in head/usr.sbin/bsdinstall: . scripts Message-ID: <20200117112151.GJ38096@zxy.spb.ru> In-Reply-To: <3b4b4bda-75a3-3019-bc02-ecd6acacd77f@grosbein.net> References: <202001150747.00F7lqiG071097@repo.freebsd.org> <CAPjTQNHa9Um%2B0S8zMD3eeop3YSdVti0o=DSv5%2BB=455wcrq3VA@mail.gmail.com> <ed0b16af-01c8-62fe-918a-3f1f9f9dcbd8@freebsd.org> <CANCZdfpOw54MQsW4aohLn3ufgEqK8beTe_EdjYktViFubPPyzg@mail.gmail.com> <aea3e071-61bd-399d-1d1f-cce4125b2480@grosbein.net> <CAPyFy2DEC=jhQdxOLjUGs9nr%2B2n733XJfWKjTKYbAY7eubRkRQ@mail.gmail.com> <fe489e0f-f05a-8d85-6ef7-0f3bd7b6f9f4@grosbein.net> <20200117000333.GI38096@zxy.spb.ru> <3b4b4bda-75a3-3019-bc02-ecd6acacd77f@grosbein.net>
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On Fri, Jan 17, 2020 at 12:12:22PM +0700, Eugene Grosbein wrote: > 17.01.2020 7:03, Slawa Olhovchenkov write: > > >>>> There are multiple scenarios there ZFS may be sub-optimal at least: small i386 virtual guests > >>>> or 32-bit only hardware like AMD Geode, or big amd64 SSD-only systems with bhyve and multiple guests > >>>> that need lots of memory and should not fight with ZFS for RAM etc. > >>> > >>> That may well be the case, but our defaults should represent the > >>> configuration that's desirable to the largest set of users, and IMO > >>> that's ZFS in most cases today. > >>> > >>> It might be that we should default to UFS on i386 and ZFS on amd64? > >> > >> UFS may be better for any virtual guest having RAM less or equal to 4GB. > > > > Why? > > Considering /usr/ports, /usr/src and /usr/obj and amount of RAM > needed to keep metadata in ZFS ARC /usr/ports, /usr/src and /usr/obj don't need be exist on low-RAM install -- use poudriere and release build on dedicated build host and applay binary update. > plus standard daily periodic scripts traveling filesystems, low-RAM virtual machine utilizing its RAM to full amount > can work reliably with UFS and hang at nights due to extra ZFS overhead in default install (not tuned). Just need fix ZFS ARC pressure and UMA zone reclaim. ZFS ARC overhead about 10-20MB (IMHO) on low-RAM install. This is negligible from 512MB.
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