From owner-freebsd-fs@freebsd.org Wed Jul 29 21:12:02 2015 Return-Path: Delivered-To: freebsd-fs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 4E1C09AEB1E for ; Wed, 29 Jul 2015 21:12:02 +0000 (UTC) (envelope-from javocado@gmail.com) Received: from mail-lb0-x230.google.com (mail-lb0-x230.google.com [IPv6:2a00:1450:4010:c04::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id CDB7213A5 for ; Wed, 29 Jul 2015 21:12:01 +0000 (UTC) (envelope-from javocado@gmail.com) Received: by lbbst4 with SMTP id st4so14820866lbb.1 for ; Wed, 29 Jul 2015 14:11:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:date:message-id:subject:from:to:content-type; bh=RJ48jI/24zAwZST9h6k7yWneTkRfFeGzWe+S9WGruE8=; b=MJylOO4orIesyRrfbfWbD82rdsJyIUDmKCDZng0GjlOAAnzi3Pu3Nd7aAx52j37Mic Tjx4QLugJDVM9hxSki/b6mwhQOq4I6pCMTmEZEtra05sYHagjIlngf6xySOpQauGZp7v D6zIyyjM2j3Re7OxbeO0SHokLpaI9ef06COG8V0ORWL9o5giFy9W2clIMoCFwMUKBtAH w6AFs+H6QjoXukpA9knZBuhdV9JSP+VTLjsqubcPWXThW+0x5Z2CiJY1cUPzH3IBhz8n GRKN8+Aa/vrkUX6aVjDW80hCqrFlUG715WnFWufjdBND6TN8u4ir9MS12tWznsMLc8d+ PcZA== MIME-Version: 1.0 X-Received: by 10.112.137.164 with SMTP id qj4mr40724648lbb.105.1438204319587; Wed, 29 Jul 2015 14:11:59 -0700 (PDT) Received: by 10.114.96.8 with HTTP; Wed, 29 Jul 2015 14:11:59 -0700 (PDT) Date: Wed, 29 Jul 2015 14:11:59 -0700 Message-ID: Subject: pw operations slow under zfs load From: javocado To: FreeBSD Filesystems Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.20 X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 29 Jul 2015 21:12:02 -0000 Hi, We have a pretty busy ZFS pool running on an 8.3 AMD system. We are noticing that when the pool is busy pw-related operations seem to take a long time to complete: # time pw unlock 1000 0.007u 0.036s 0:39.72 0.0% 45+1953k 0+113io 0pf+0w # time pw lock 1000 0.032u 0.022s 1:09.63 0.0% 24+1132k 0+114io 0pf+0w Wile the command is running, we note that the process is locked in the D state: root 85051 0.0 0.0 5832 960 0 D+ 1:53PM 0:00.02 /usr/sbin/pwd_mkdb -u 1000 /etc/master.passwd We also note that there is next to 0 disk activity on the boot volume: # gstat -f ad dT: 1.005s w: 1.000s filter: ad L(q) ops/s r/s kBps ms/r w/s kBps ms/w %busy Name 0 0 0 0 0.0 0 0 0.0 0.0| ad6 0 0 0 0 0.0 0 0 0.0 0.0| ad8 0 0 0 0 0.0 0 0 0.0 0.0| ad10 0 0 0 0 0.0 0 0 0.0 0.0| ad12 And plenty of free mem: Mem: 400M Active, 3391M Inact, 128G Wired, 1935M Cache, 14G Buf, 6055M Free So, what's going on here? How does a busy pool with it's own set of drives (which operate off an HBA) affect the speed of operations involving the boot volume (an SSD connected to the mobo)?