From owner-freebsd-fs@freebsd.org Mon Jan 21 14:17:15 2019 Return-Path: Delivered-To: freebsd-fs@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 2FA1E14AAED3 for ; Mon, 21 Jan 2019 14:17:15 +0000 (UTC) (envelope-from borjam@sarenet.es) Received: from cu01176b.smtpx.saremail.com (cu01176b.smtpx.saremail.com [195.16.151.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 555718B4F7 for ; Mon, 21 Jan 2019 14:17:13 +0000 (UTC) (envelope-from borjam@sarenet.es) Received: from [172.16.8.5] (unknown [192.148.167.11]) by proxypop01.sare.net (Postfix) with ESMTPA id 2ADB89DDD8C; Mon, 21 Jan 2019 15:17:10 +0100 (CET) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 12.2 \(3445.102.3\)) Subject: Re: ZFS on Hardware RAID From: Borja Marcos In-Reply-To: Date: Mon, 21 Jan 2019 15:17:08 +0100 Cc: andy thomas , freebsd-fs Content-Transfer-Encoding: quoted-printable Message-Id: <92746659-4B3F-415C-BB6A-6C99837AFAF2@sarenet.es> References: <1180280695.63420.1547910313494.JavaMail.zimbra@gausus.net> <92646202.63422.1547910433715.JavaMail.zimbra@gausus.net> <1691666278.63816.1547976245836.JavaMail.zimbra@gausus.net> To: jdelisle X-Mailer: Apple Mail (2.3445.102.3) X-Rspamd-Queue-Id: 555718B4F7 X-Spamd-Bar: / Authentication-Results: mx1.freebsd.org; spf=pass (mx1.freebsd.org: domain of borjam@sarenet.es designates 195.16.151.151 as permitted sender) smtp.mailfrom=borjam@sarenet.es X-Spamd-Result: default: False [-0.59 / 15.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; NEURAL_HAM_MEDIUM(-0.34)[-0.338,0]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; R_SPF_ALLOW(-0.20)[+ip4:195.16.150.0/23]; MV_CASE(0.50)[]; MIME_GOOD(-0.10)[text/plain]; RCVD_TLS_LAST(0.00)[]; DMARC_NA(0.00)[sarenet.es]; NEURAL_SPAM_SHORT(0.53)[0.532,0]; NEURAL_HAM_LONG(-0.98)[-0.983,0]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_ALL(0.00)[]; MX_GOOD(-0.01)[cached: smtp.sarenet.es]; RCVD_IN_DNSWL_NONE(0.00)[151.151.16.195.list.dnswl.org : 127.0.10.0]; IP_SCORE(0.01)[country: ES(0.05)]; FREEMAIL_TO(0.00)[gmail.com]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:3262, ipnet:195.16.128.0/19, country:ES]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Jan 2019 14:17:15 -0000 > On 20 Jan 2019, at 16:33, jdelisle wrote: > I can say for certain that with Dell PERC 6/e RAID (SAS 8087ELP based) > cards, when the virtual devices are entire disks each in a RAID0 > configuration, the way the adapter writes data to them is effectively = the > same as JBOD. You can take a RAID0 drive from a PERC 6/e controller = and > use in with an HBA/ "IT Mode" JBOD controller without issue. I = personally > migrated 14x 1TB drives off PERC 6/e (all RAID0's) to a SAS 6gbps HBA, = and > my ZFS VDEV's and pools were totally fine. You can move back and = forth no > problem. I can't say this is the case for ALL RAID controllers, I've = only > done this with an old PERC 6/e. However a single disk RAID0 volume (what manufacturers call a JBOD) is = not the same=20 as a disk. With the =E2=80=9Cvirtual JBOD=E2=80=9D you lose direct CAM = access, which means that some advanced options won=E2=80=99t be supported. For example, if you are using SSDs ZFS knows when to issue a TRIM (or, = in general, BIO_DELETE) command. Does the =E2=80=9Cvirtual JBOD=E2=80=9D offer that = option?=20 The same could be said of other functionalities available when you talk = directly to the disks. > That's why I did as I describe above. I didn't have the money to buy = an > HBA until a year or two later, and I had good backups, so I used the = PERC > 6/e. Depending on the LSI model used in that card you can make it behave like = an HBA.=20 Borja.