From owner-freebsd-questions@freebsd.org Thu Apr 23 22:57:32 2020 Return-Path: Delivered-To: freebsd-questions@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id B2B4F2C610A for ; Thu, 23 Apr 2020 22:57:32 +0000 (UTC) (envelope-from freebsd@theory14.net) Received: from bacon.theory14.net (bacon.theory14.net [45.55.200.27]) by mx1.freebsd.org (Postfix) with ESMTP id 497Xkg3f6Hz4RS8 for ; Thu, 23 Apr 2020 22:57:31 +0000 (UTC) (envelope-from freebsd@theory14.net) Received: from remote.theory14.net (remote.theory14.net [72.66.31.190]) by bacon.theory14.net (Postfix) with ESMTPSA id 02A73125ECE; Thu, 23 Apr 2020 18:57:24 -0400 (EDT) Received: from grackle.int.theory14.net (grackle.int.theory14.net [192.168.10.52]) by remote.theory14.net (Postfix) with ESMTPS id C38E4429D; Thu, 23 Apr 2020 18:57:24 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=theory14.net; s=mail; t=1587682644; bh=Z3KCNrcMSWc+3b4UMyBkkBbyvbrmSBXhiSm5pvkFoqs=; h=Subject:From:In-Reply-To:Date:Cc:References:To; b=oXec+ofOPWeAUldj4DsJsYQBHrxojVVNRXICGl+bclgbqDiYOCOUu3b8RAd2EvsUp dOzBagPAGuTe/FL32Cd/646uuCYgnR63Ts7bjM28BQ8KMb52azorhp1N8Ov/kLEy4u Sp9cmYQXN9hnZBEVs2pKAbeia6ssSc9BHMlQyyNs= Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 13.4 \(3608.80.23.2.2\)) Subject: Re: best upgrade process for server From: Chris Gordon In-Reply-To: <618aed37-a64b-9471-4353-366460d057d7@holgerdanske.com> Date: Thu, 23 Apr 2020 18:57:24 -0400 Cc: freebsd-questions@freebsd.org Content-Transfer-Encoding: quoted-printable Message-Id: <22A86243-7351-4A2F-8B43-10E80C61901E@theory14.net> References: <1810714722.149383351.1587616694832.JavaMail.zimbra@shaw.ca> <618aed37-a64b-9471-4353-366460d057d7@holgerdanske.com> To: David Christensen X-Mailer: Apple Mail (2.3608.80.23.2.2) X-Rspamd-Queue-Id: 497Xkg3f6Hz4RS8 X-Spamd-Bar: - Authentication-Results: mx1.freebsd.org; dkim=pass header.d=theory14.net header.s=mail header.b=oXec+ofO; dmarc=pass (policy=none) header.from=theory14.net; spf=pass (mx1.freebsd.org: domain of freebsd@theory14.net designates 45.55.200.27 as permitted sender) smtp.mailfrom=freebsd@theory14.net X-Spamd-Result: default: False [-1.16 / 15.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; R_DKIM_ALLOW(-0.20)[theory14.net:s=mail]; NEURAL_HAM_MEDIUM(-0.98)[-0.979,0]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+mx]; MV_CASE(0.50)[]; MIME_GOOD(-0.10)[text/plain]; NEURAL_HAM_LONG(-0.99)[-0.994,0]; RCVD_COUNT_THREE(0.00)[3]; TO_MATCH_ENVRCPT_SOME(0.00)[]; DKIM_TRACE(0.00)[theory14.net:+]; RCPT_COUNT_TWO(0.00)[2]; DMARC_POLICY_ALLOW(-0.50)[theory14.net,none]; RCVD_NO_TLS_LAST(0.10)[]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; IP_SCORE(1.21)[ipnet: 45.55.192.0/18(4.89), asn: 14061(1.22), country: US(-0.05)]; ASN(0.00)[asn:14061, ipnet:45.55.192.0/18, country:US]; MID_RHS_MATCH_FROM(0.00)[]; RECEIVED_SPAMHAUS_PBL(0.00)[190.31.66.72.khpj7ygk5idzvmvt5x4ziurxhy.zen.dq.spamhaus.net : 127.0.0.10] X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 Apr 2020 22:57:32 -0000 > On Apr 23, 2020, at 4:25 PM, David Christensen = wrote: >=20 > When it was time to retire my previous desktop/ Linux SOHO server with = an up-to-date FreeBSD server, I bought a lightly used Dell PowerEdge T30 = with one Xeon E3-1225 v5 processor, one 8 GB ECC memory module, one 1 TB = SATA HDD, and one DVD+/-RW drive. (It is important that computers = running ZFS have ECC memory.) I would clarify the statement about ECC memory in that ECC memory is = important for any system where memory errors are significantly = detrimental to the applications running on the server whereas to justify = the additional cost. =20 As for file systems, ECC memory is no more or less important for ZFS, = UFS, ext*, NTFS, etc. The only case where I think the argument for ZFS = could be stronger than other file systems is by virtue of ZFS typically = using more memory for the ARC and thereby theoretically increasing the = probability of a read serviced from ARC experiencing a bit flip. This = thinking, though, applies to applications, too -- as more memory is = used, the probability of encountering a memory error increases. The = idea that ZFS uniquely "requires" ECC memory to be "safe" often seems to = stem back to an a blog post about the "scrub of death". This has been = debunked many times. Allan Jude discusses this is far more detail and = expertise than I can starting at about minute 57 of Episode 200 of the = BSDNOw podcast: = https://www.jupiterbroadcasting.com/116226/getting-scrubbed-to-death-bsd-n= ow-200/ That said, if you can afford ECC memory, you're better than without it. = You are even better with backups that are on something other than the = machine you're backing up. You're even better if you can periodically = test those backups and validate that they are indeed good and = recoverable. Chris=