From owner-freebsd-hackers@freebsd.org Sat Dec 1 22:40:44 2018 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 99319132A496 for ; Sat, 1 Dec 2018 22:40:44 +0000 (UTC) (envelope-from phk@critter.freebsd.dk) Received: from phk.freebsd.dk (phk.freebsd.dk [130.225.244.222]) by mx1.freebsd.org (Postfix) with ESMTP id 164517779D for ; Sat, 1 Dec 2018 22:40:44 +0000 (UTC) (envelope-from phk@critter.freebsd.dk) Received: from critter.freebsd.dk (unknown [192.168.55.3]) by phk.freebsd.dk (Postfix) with ESMTP id 48C17148C9; Sat, 1 Dec 2018 22:40:43 +0000 (UTC) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.15.2/8.15.2) with ESMTPS id wB1MegE7001205 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Sat, 1 Dec 2018 22:40:43 GMT (envelope-from phk@critter.freebsd.dk) Received: (from phk@localhost) by critter.freebsd.dk (8.15.2/8.15.2/Submit) id wB1MegSt001179; Sat, 1 Dec 2018 22:40:42 GMT (envelope-from phk) To: RW , RW via freebsd-hackers Subject: Re: How to use trim command ?,Re: How to use trim command ? In-reply-to: <20181201222424.0ae8abfd@gumby.homeunix.com> From: "Poul-Henning Kamp" References: <7e69211c-6ffb-6155-b17a-a845c0b3586d@grosbein.net> <20181201.093153.893601099798031027.ish@amail.plala.or.jp> <1c7139bd-258c-e7d2-2572-052da3803b3b@freebsd.org> <20181201.202332.546134930481017424.ish@amail.plala.or.jp> <12404.1543699424@critter.freebsd.dk> <20181201222424.0ae8abfd@gumby.homeunix.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <1174.1543704042.1@critter.freebsd.dk> Content-Transfer-Encoding: quoted-printable Date: Sat, 01 Dec 2018 22:40:42 +0000 Message-ID: <1177.1543704042@critter.freebsd.dk> X-Rspamd-Queue-Id: 164517779D X-Spamd-Result: default: False [5.32 / 15.00]; ARC_NA(0.00)[]; FROM_HAS_DN(0.00)[]; NEURAL_SPAM_SHORT(0.88)[0.881,0]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[freebsd.dk]; AUTH_NA(1.00)[]; NEURAL_SPAM_MEDIUM(0.92)[0.921,0]; RCVD_COUNT_THREE(0.00)[4]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_ALL(0.00)[]; MX_GOOD(-0.01)[cached: phk.freebsd.dk]; RCPT_COUNT_TWO(0.00)[2]; NEURAL_SPAM_LONG(0.96)[0.957,0]; R_SPF_NA(0.00)[]; FORGED_SENDER(0.30)[phk@phk.freebsd.dk,phk@critter.freebsd.dk]; FREEMAIL_TO(0.00)[googlemail.com]; RCVD_NO_TLS_LAST(0.10)[]; R_DKIM_NA(0.00)[]; SUBJECT_ENDS_QUESTION(1.00)[]; ASN(0.00)[asn:1835, ipnet:130.225.0.0/16, country:EU]; FROM_NEQ_ENVFROM(0.00)[phk@phk.freebsd.dk,phk@critter.freebsd.dk]; IP_SCORE(0.27)[asn: 1835(1.36), country: EU(0.00)] X-Rspamd-Server: mx1.freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 01 Dec 2018 22:40:44 -0000 -------- In message <20181201222424.0ae8abfd@gumby.homeunix.com>, RW via freebsd-ha= ckers writes: >On Sat, 01 Dec 2018 21:23:44 +0000 >> Why would you run 'fsck_ffs -E' in cron anyway ? >> = >> If the file-system is has TRIM enabled, it would be a no-op, unless >> there are bugs in the fs ? > >There's a school of thought that trimming in real-time, after file >deletion, slows down I/O on the device. I suspect people would have reached that conclusion back when various shady outfits started selling camera-grade FAL devices in 2.5" form-factor. My advice would be to avoid any device where that pattern is observed, because that means there is too few write buffers and paths. -- = Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe = Never attribute to malice what can adequately be explained by incompetence= .