From owner-freebsd-hackers Mon Mar 5 16:31:50 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from earth.backplane.com (earth-nat-cw.backplane.com [208.161.114.67]) by hub.freebsd.org (Postfix) with ESMTP id B373437B719 for ; Mon, 5 Mar 2001 16:31:45 -0800 (PST) (envelope-from dillon@earth.backplane.com) Received: (from dillon@localhost) by earth.backplane.com (8.11.2/8.9.3) id f260VjC47207; Mon, 5 Mar 2001 16:31:45 -0800 (PST) (envelope-from dillon) Date: Mon, 5 Mar 2001 16:31:45 -0800 (PST) From: Matt Dillon Message-Id: <200103060031.f260VjC47207@earth.backplane.com> To: Dan Phoenix Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: systat -vmstat or iostat IO help References: Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG :systat -vmstat : :Disks ad0 acd0 fd0 md0 89 ofod intrn :KB/t 4.35 0.00 0.00 0.00 85 %slo-z 61952 buf :tps 13 0 0 0 104 tfree 42 dirtybuf :MB/s 0.05 0.00 0.00 0.00 36095 desiredvnodes :% busy 100 0 0 0 58692 numvnodes : :well vmstat showing 100% busy and iostat showing 10% busy...... :IO an issue here or not? :... :Dan systat -vmstat is correct. I usually use 'systat -vm 1'. If you see 100% busy for more then a few seconds then the disk is saturated (almost certainly seek-limited). Solutions depend on what the system is doing. Mail systems are the least scaleable, requiring you to add additional disks for spools or a stripe, or additional machines and use an MX round robin. Most other services can be scaled well simply by adding memory or cpu. SCSI disks usually do better then IDE in seek-limited situations. Higher-RPM disks can make a big difference too. -Matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message