From nobody Mon Apr 18 18:11:27 2022 X-Original-To: freebsd-scsi@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 932485D6BC6 for ; Mon, 18 Apr 2022 18:11:38 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from wout2-smtp.messagingengine.com (wout2-smtp.messagingengine.com [64.147.123.25]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4Khw494t8kz3n1d for ; Mon, 18 Apr 2022 18:11:37 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailout.west.internal (Postfix) with ESMTP id 826AD320210B; Mon, 18 Apr 2022 14:11:29 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute3.internal (MEProxy); Mon, 18 Apr 2022 14:11:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsco.org; h=cc :cc:content-transfer-encoding:content-type:date:date:from:from :in-reply-to:in-reply-to:message-id:mime-version:references :reply-to:sender:subject:subject:to:to; s=fm3; t=1650305488; x= 1650391888; bh=eTjC5U50c/LJtmTBZ/oL+817BIcuQwI8yNf2RJc+/cU=; b=a L4PGvxWwWOw2YbenFe/jEDQ/rw2ihALTUmf0MYAJfovWLsYTTEQVyqwml25PD+iQ XGU20VaEzEoZD0H4uCclLdmj7zjVXpCQq5dRXaKGI/MbBlcd31RnWKr2x5FcXxIU 04P+P/q9n+y2jgUZKhOd3M42xWhscpHYA4Cdq522YuwLtQ52HrD560mPIoutz6PE yZwipu0r1cwfYTZe3/kfFyt/1tivGJfQv5tS91qJKloosrFFy7aIBXylwQZa0n5w FN1twfrdeWKuVbW0Lrx0OIye+dh3bje5qxaBRfJRU4WlGyNfFzOLwQRl9fAJ2J2v AmSzaX2lwNHZxGMo6Pl6Q== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding :content-type:date:date:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm1; t=1650305488; x=1650391888; bh=eTjC5U50c/LJt mTBZ/oL+817BIcuQwI8yNf2RJc+/cU=; b=zgqvSDlpQNb32/APaCK5E7/2OJYXq TFTBbHV+22vsuKg53LteHw359k8YiKZnmwfpAw1azEuyvk8GjAEiJyJwerxOFChe XyHTwQ9kFcbuNJlpQpehJcG97PZjGgDkBQqRQP1qGxsb0UNOEdJD34Ym9wdf+ZG4 pXkC4cHCHIyJ7Tlkze6wm4T56IiDJS31YXKTGt+i7OvdYdlWzl8aSO8zbQxkCmgB TBLOyvp0/UIoBHPSSuLkEXhpZrdICKMZa6DqltW5OuPWqLIu6JVRyWTqKXSPJdXM +ilGt9PYT8I/NptMjd19L1p+XAzpO516o77D6HHh1JIb0zSLYicCN0V2Q== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvvddrvddtuddguddvvdcutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecunecujfgurheptggguffhjgffgffkfhfvofesth hqmhdthhdtjeenucfhrhhomhepufgtohhtthcunfhonhhguceoshgtohhtthhlsehsrghm shgtohdrohhrgheqnecuggftrfgrthhtvghrnhepfeejgefgjefhgfdtjeevjeekgeevie elueehjefgudetvefgtdetgffggefgvdegnecuvehluhhsthgvrhfuihiivgeptdenucfr rghrrghmpehmrghilhhfrhhomhepshgtohhtthhlsehsrghmshgtohdrohhrgh X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Mon, 18 Apr 2022 14:11:28 -0400 (EDT) Content-Type: text/plain; charset=utf-8 List-Id: SCSI subsystem List-Archive: https://lists.freebsd.org/archives/freebsd-scsi List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-scsi@freebsd.org X-BeenThere: freebsd-scsi@freebsd.org Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.80.82.1.1\)) Subject: Re: WWN From: Scott Long In-Reply-To: Date: Mon, 18 Apr 2022 12:11:27 -0600 Cc: freebsd-scsi Content-Transfer-Encoding: quoted-printable Message-Id: References: To: Warner Losh X-Mailer: Apple Mail (2.3696.80.82.1.1) X-Rspamd-Queue-Id: 4Khw494t8kz3n1d X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=samsco.org header.s=fm3 header.b="a L4PGvx"; dkim=pass header.d=messagingengine.com header.s=fm1 header.b=zgqvSDlp; dmarc=none; spf=pass (mx1.freebsd.org: domain of scottl@samsco.org designates 64.147.123.25 as permitted sender) smtp.mailfrom=scottl@samsco.org X-Spamd-Result: default: False [-3.87 / 15.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; MV_CASE(0.50)[]; R_SPF_ALLOW(-0.20)[+ip4:64.147.123.25]; RCVD_COUNT_THREE(0.00)[4]; TO_DN_ALL(0.00)[]; DKIM_TRACE(0.00)[samsco.org:+,messagingengine.com:+]; RCPT_COUNT_TWO(0.00)[2]; SUBJ_ALL_CAPS(0.23)[3]; NEURAL_HAM_SHORT(-1.00)[-1.000]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_LAST(0.00)[]; ASN(0.00)[asn:29838, ipnet:64.147.123.0/24, country:US]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_IN_DNSWL_LOW(-0.10)[64.147.123.25:from]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[samsco.org:s=fm3,messagingengine.com:s=fm1]; FREEFALL_USER(0.00)[scottl]; FROM_HAS_DN(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[samsco.org]; DWL_DNSWL_LOW(-1.00)[messagingengine.com:dkim]; TO_MATCH_ENVRCPT_SOME(0.00)[]; MLMMJ_DEST(0.00)[freebsd-scsi] X-ThisMailContainsUnwantedMimeParts: N It=E2=80=99s been inertia from the hardware standpoint. SATA was = notorious for having unusable WWNs, serial numbers, etc. It=E2=80=99s = also been complicated by the varying quality of SATL and SATA-pass-thru = implementations in controllers (i.e. LSI). The Spectra guys probably = have a lot of good experience to share here. Keep VM=E2=80=99s in mind though. Emulated environments don=E2=80=99t = always try very hard to generate unique IDs for storage. It might be = possible to heuristically figure out what kind of environment the system = is in and whether the IDs are dependable. Scott > On Apr 18, 2022, at 11:47 AM, Warner Losh wrote: >=20 > Is there a reason we don't rely primarily on WWN changing to detect a = disk change at a particular location? I know it's not universally = available, but anything made in the last 15 or 20 years should have one = if my research is correct... Or is this just a case of inertia? >=20 > I'm looking at making ahci a little more resilient to transient = outages, and thought it might be best to key primarily off this and = secondarily off other changed information when that's not available. If = I had a WWN, then I'd know the disk that was gone for 500ms is the same = one and I could resume its operations and still detect that someone = unplugged drive A and plugged in drive B. >=20 > Warner >=20