Date: Thu, 9 Aug 2001 22:14:53 -0500 From: mikea <mikea@mikea.ath.cx> To: stable@FreeBSD.ORG Subject: Re: Strange I/O behavior Message-ID: <20010809221453.A1165@mikea.ath.cx> In-Reply-To: <15218.65134.426946.295368@nomad.yogotech.com>; from nate@yogotech.com on Thu, Aug 09, 2001 at 03:19:42PM -0600 References: <15218.65134.426946.295368@nomad.yogotech.com>
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On Thu, Aug 09, 2001 at 03:19:42PM -0600, Nate Williams wrote: > I've got a dual-CPU box that's acting very strangely. At various times > throughout the day, the box starts to crawl. > > In analyzing it, the only thing that jumps out at me is that the first > fixed disk is running a huge number of I/O transactions, to the point > that it's almost saturating the disk. > > However, the amount transferred is almost nil, but since this disk > contains / and /usr (which means all the files are on it), interactive > performance goes to the dump during these sessions. > > The box is an all SCSI system, with the first disk being a 17GB > Seagate. The dmesg is below. > > Here's the output of iostat 2, which shows alot of transactions going > on. However, there are no active users doing anything as far as I can > see, and top shows the system as being mostly idle. > > Any ideas how I can determine which application(s) are causing the huge > I/O loads? Try fstat and lsof to see what programs have what files open, for a start. Is there _any_ chance you've been cracked and the cracker had a tool running that spawned a few zillion telnet sessions? That happened to me last week, causing a rebuild from CDROM and some rethinking on my firewall rules. The symptoms were one CPU 97% busy with a program I didn't recognize, and some hundreds of telnet sessions outbound. -- Mike Andrews mikea@mikea.ath.cx Tired old sysadmin since 1964 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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