Date: Fri, 10 Aug 2001 16:19:56 -0600 From: Nate Williams <nate@yogotech.com> To: mikea <mikea@mikea.ath.cx> Cc: stable@FreeBSD.ORG Subject: Re: Strange I/O behavior Message-ID: <15220.24076.57998.200803@nomad.yogotech.com> In-Reply-To: <20010809221453.A1165@mikea.ath.cx> References: <15218.65134.426946.295368@nomad.yogotech.com> <20010809221453.A1165@mikea.ath.cx>
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> > 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. Nothing obvious. > Is there _any_ chance you've been cracked and the > cracker had a tool running that spawned a few zillion telnet > sessions? Not a chance. The box isn't/has never been on the Internet, and was just recently updated to 4.3-RELEASE. (I know, 4.4-RELEASE is almost out, but it's a production box>) > The symptoms were one CPU 97% busy with a program I didn't > recognize, and some hundreds of telnet sessions outbound. Interestingly enough, it's an I/O only problem. The CPU usage is barely creeping about 0.1%. Nate To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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