From nobody Fri Mar 25 13:49:38 2022 X-Original-To: freebsd-fs@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 96E501A33983 for ; Fri, 25 Mar 2022 13:49:44 +0000 (UTC) (envelope-from bsdlists@jld3.net) Received: from mail.jld3.net (mail.jld3.net [45.55.236.93]) (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 4KQ3P15SVwz3QkV for ; Fri, 25 Mar 2022 13:49:41 +0000 (UTC) (envelope-from bsdlists@jld3.net) Received: from localhost (localhost [127.0.0.1]) by mail.jld3.net (Postfix) with ESMTP id 1FB15415F2; Fri, 25 Mar 2022 07:49:40 -0600 (MDT) X-Virus-Scanned: amavisd-new at jld3.net Received: from mail.jld3.net ([127.0.0.1]) by localhost (mail.jld3.net [127.0.0.1]) (amavisd-new, port 10024) with LMTP id Uzpz5p0Rrep5; Fri, 25 Mar 2022 07:49:39 -0600 (MDT) Received: from [169.254.207.51] (c-24-9-144-115.hsd1.co.comcast.net [24.9.144.115]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: jld) by mail.jld3.net (Postfix) with ESMTPSA id 1179440615; Fri, 25 Mar 2022 07:49:39 -0600 (MDT) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.jld3.net 1179440615 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.jld3.net 1179440615 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=jld3.net; s=8d052f02dde2; t=1648216179; bh=yYVyBhs6Op3R2mQOLwvQr0DxzHX62xInBuTK61GIsug=; h=From:To:Subject:Date:Message-ID:MIME-Version:From; b=Le3n1A1sJV7x8jlRRUUl+6Iy2ox1PBnZBhq9K0JMDqoyHWm9s13icmEGEphuCJk1l 5HcLmibiYJiHsl1aTKCJTe2zWk83UaanGcu8tkey1CAUZlGzrQmUE3hVS+dxi0/nWP 1ryEJUfZEHrW3rvY/FSLo6ZMoYwYF+3l801JBR+E= From: "John Doherty" To: Rich Cc: freebsd-fs Subject: Re: create zpool from zvols? Date: Fri, 25 Mar 2022 07:49:38 -0600 X-Mailer: MailMate (1.13.2r5673) Message-ID: In-Reply-To: References: <72AA1AC8-E623-4B73-A3F3-3FDB0ABDFCEA@jld3.net> List-Id: Filesystems List-Archive: https://lists.freebsd.org/archives/freebsd-fs List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-fs@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; format=flowed X-Rspamd-Queue-Id: 4KQ3P15SVwz3QkV X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=jld3.net header.s=8d052f02dde2 header.b=Le3n1A1s; dmarc=pass (policy=quarantine) header.from=jld3.net; spf=pass (mx1.freebsd.org: domain of bsdlists@jld3.net designates 45.55.236.93 as permitted sender) smtp.mailfrom=bsdlists@jld3.net X-Spamd-Result: default: False [-3.00 / 15.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; R_DKIM_ALLOW(-0.20)[jld3.net:s=8d052f02dde2]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+ip4:45.55.236.93]; NEURAL_HAM_LONG(-1.00)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCVD_COUNT_THREE(0.00)[4]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_ALL(0.00)[]; DKIM_TRACE(0.00)[jld3.net:+]; RCPT_COUNT_TWO(0.00)[2]; DMARC_POLICY_ALLOW(-0.50)[jld3.net,quarantine]; NEURAL_HAM_SHORT(-1.00)[-1.000]; MLMMJ_DEST(0.00)[freebsd-fs]; FREEMAIL_TO(0.00)[gmail.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; SUBJECT_ENDS_QUESTION(1.00)[]; ASN(0.00)[asn:14061, ipnet:45.55.192.0/18, country:US]; RCVD_TLS_LAST(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; RECEIVED_SPAMHAUS_PBL(0.00)[24.9.144.115:received] X-ThisMailContainsUnwantedMimeParts: N Thanks for the super-quick response. I guess I'll just use plain files then. I don't really want to use the zpools for anything, I just want an easy way to experiment with and demonstrate zpool create commands. FWIW, the tunable does allow the "zpool create" command to work: [root@ibex] # sysctl vfs.zfs.vol.recursive vfs.zfs.vol.recursive: 1 [root@ibex] # zpool create ztest mirror /dev/zvol/zroot/zv{0,1} [root@ibex] # zpool status ztest pool: ztest state: ONLINE config: NAME STATE READ WRITE CKSUM ztest ONLINE 0 0 0 mirror-0 ONLINE 0 0 0 zvol/zroot/zv0 ONLINE 0 0 0 zvol/zroot/zv1 ONLINE 0 0 0 errors: No known data errors On Fri 2022-03-25 07:41 AM MDT -0600, wrote: > https://reviews.freebsd.org/D4998 added a knob to allow you to do this > even > though it sometimes deadlocks, which is why it's off by default. > > It's a FreeBSD-only tunable. > > That tunable is still there in the post-OpenZFS FreeBSD, too, though > it's > labeled "Allow zpools to use zvols as vdevs (DANGEROUS)", so it seems > likely that it still can cause undesirable outcomes. > > - Rich > > > > On Fri, Mar 25, 2022 at 9:34 AM John Doherty > wrote: > >> Hello, I am using ZFS on FreeBSD 13.0-RELEASE-p8. For experimentation >> and demonstration, I would like to create zpools using zvols as the >> underlying block devices. >> >> For example, I have these: >> >> [root@ibex] # zfs list -r -t volume zroot | grep zv >> zroot/zv0 8.25G 832G 56K - >> zroot/zv1 8.25G 832G 56K - >> >> This seems as if it would do what I want: >> >> [root@ibex] # zpool create -n ztest mirror /dev/zvol/zroot/zv{0,1} >> would create 'ztest' with the following layout: >> >> ztest >> mirror >> zvol/zroot/zv0 >> zvol/zroot/zv1 >> >> But when I try to actually do it, it doesn't work: >> >> [root@ibex] # zpool create ztest mirror /dev/zvol/zroot/zv{0,1} >> cannot create 'ztest': no such pool or dataset >> >> FWIW, doing something similar on OmniOS works fine: >> >> [root@orca] # uname -srvp >> SunOS 5.11 omnios-r151040-852962cae3 i386 >> [root@orca] # zfs create -V 2G rpool/zv0 >> [root@orca] # zfs create -V 2G rpool/zv1 >> [root@orca] # zpool create ztest mirror /dev/zvol/dsk/rpool/zv{0,1} >> [root@orca] # zpool status ztest >> pool: ztest >> state: ONLINE >> scan: none requested >> config: >> >> NAME STATE READ WRITE CKSUM >> ztest ONLINE 0 0 0 >> mirror-0 ONLINE 0 0 0 >> /dev/zvol/dsk/rpool/zv0 ONLINE 0 0 0 >> /dev/zvol/dsk/rpool/zv1 ONLINE 0 0 0 >> >> errors: No known data errors >> >> I thought I had done this in the past. Am I doing something wrong? Am >> I >> misremembering and this never worked? >> >> Using files created with truncate(1) rather zvols seems to work fine >> so >> maybe that's what I did before. Not sure, it's been a long time since >> I >> wanted to do something like this. >> >> Thanks for any enlightenment.