From nobody Wed Nov 22 06:49:31 2023 X-Original-To: freebsd-stable@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 4SZsLJ4DmYz51yY0 for ; Wed, 22 Nov 2023 06:49:44 +0000 (UTC) (envelope-from jonc@chen.org.nz) Received: from egress.chen.org.nz (egress.chen.org.nz [170.75.172.82]) by mx1.freebsd.org (Postfix) with ESMTP id 4SZsLH1vj6z4Vc5 for ; Wed, 22 Nov 2023 06:49:43 +0000 (UTC) (envelope-from jonc@chen.org.nz) Authentication-Results: mx1.freebsd.org; dkim=none; spf=pass (mx1.freebsd.org: domain of jonc@chen.org.nz designates 170.75.172.82 as permitted sender) smtp.mailfrom=jonc@chen.org.nz; dmarc=none Received: from mail.chen.org.nz (unknown [210.54.37.164]) by egress.chen.org.nz (Postfix) with ESMTP id 22827EAEAA for ; Wed, 22 Nov 2023 19:49:09 +1300 (NZDT) Received: from mail.chen.org.nz (localhost [127.0.0.1]) by filter.inside.chen.org.nz (Postfix) with ESMTP id 0E54018120 for ; Wed, 22 Nov 2023 19:49:33 +1300 (NZDT) X-Spam-Checker-Version: SpamAssassin 4.0.0 (2022-12-14) on ametrine.inside.chen.org.nz Received: from [192.168.1.10] (jade.inside.chen.org.nz [192.168.1.10]) by mail.chen.org.nz (Postfix) with ESMTPS id 03F6418348 for ; Wed, 22 Nov 2023 19:49:33 +1300 (NZDT) Message-ID: Date: Wed, 22 Nov 2023 19:49:31 +1300 List-Id: Production branch of FreeBSD source code List-Archive: https://lists.freebsd.org/archives/freebsd-stable List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-stable@freebsd.org X-BeenThere: freebsd-stable@freebsd.org MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: freebsd-stable@freebsd.org From: Jonathan Chen Subject: Unusual ZFS behaviour Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spamd-Result: default: False [-3.19 / 15.00]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-1.00)[-1.000]; R_SPF_ALLOW(-0.20)[+a:egress.chen.org.nz]; RCVD_NO_TLS_LAST(0.10)[]; MIME_GOOD(-0.10)[text/plain]; XM_UA_NO_VERSION(0.01)[]; MLMMJ_DEST(0.00)[freebsd-stable@freebsd.org]; R_DKIM_NA(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; DMARC_NA(0.00)[chen.org.nz]; ARC_NA(0.00)[]; ASN(0.00)[asn:174, ipnet:170.75.160.0/20, country:US]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; RCVD_COUNT_THREE(0.00)[3]; PREVIOUSLY_DELIVERED(0.00)[freebsd-stable@freebsd.org]; RCPT_COUNT_ONE(0.00)[1]; TO_DN_NONE(0.00)[]; MID_RHS_MATCH_FROM(0.00)[] X-Rspamd-Queue-Id: 4SZsLH1vj6z4Vc5 X-Spamd-Bar: --- Hi, I'm running a somewhat recent version of STABLE-13/amd64: stable/13-n256681-0b7939d725ba: Fri Nov 10 08:48:36 NZDT 2023, and I'm seeing some unusual behaviour with ZFS. To reproduce: 1. one big empty disk, GPT scheme, 1 freebsd-zfs partition. 2. create a zpool, eg: tank 3. create 2 sub-filesystems, eg: tank/one, tank/two 4. fill each sub-filesystem with large files until the pool is ~80% full. In my case I had 200 10Gb files in each. 5. in one session run 'md5 tank/one/*' 6. in another session run 'md5 tank/two/*' For most of my runs, one of the sessions against a sub-filesystem will be starved of I/O, while the other one is performant. Is anyone else seeing this? -- Jonathan Chen