Date: Thu, 24 Nov 2005 14:36:01 -0700 From: Dan Charrois <dan@syz.com> To: freebsd-stable@freebsd.org Subject: Re: FreeBSD unstable on Dell 1750 using SMP? Message-ID: <83BB6E6C-AF9B-4B1F-9D89-C170E98AECFF@syz.com>
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Hi Kris, Rutger, and others that have commented on this thread. I'm happy to hear that I'm not the only one experiencing problems like this. I posted a similar question a month or so ago about a PowerEdge 2850 using SMP (dual Xeons) and never received any responses that helped solve the problem, or even any indication that others had the same problem. As you know, troubleshooting this is quite difficult, since it can take weeks to go down, and then the "auto-reboot" doesn't result in any clues as to why in the log file - it's just suddenly started again as if someone had pulled the plug on it. I've been pulling my hair out. My machine crashed twice in the last month or so, within two weeks of each other. Both times, it was just as a cron task was about to schedule the mysqlhotcopy script to back up some SQL databases that are being hosted on that machine, so I thought it may have something to do with that (I had it running as a root crontask so figured that maybe some bug in that caused things to go weird - it was running as root, after all). I changed it to run under a less privileged user and the machine hasn't died for about 2 1/2 weeks. But that's hardly a conclusive case of having solved the situation - it's probably planning on surviving just long enough to last until the point I need it the most to work. It sounds as though memory buffer allocations are going wacky or something, in which anything could take it down given the wrong combination of events. In any case, We're running the amd64 version of FreeBSD 5.4-RELEASE- p6 FreeBSD 5.4-RELEASE-p6 #3: Fri Aug 5 18:18:10 MDT 2005 A netstat -m (which I'd never tried before) yields: 18446744073709551402 mbufs in use 49/25600 mbuf clusters in use (current/max) 0/0/0 sfbufs in use (current/peak/max) 44 KBytes allocated to network 0 requests for sfbufs denied 0 requests for sfbufs delayed 0 requests for I/O initiated by sendfile 884 calls to protocol drain routines Obviously, the mbufs in use currently on that machine is way out to lunch. And interestingly, it looks as though my max mbuf clusters in use of 25600 is identical to the other netstat -m reports from people having this problem. Another machine (an older single CPU Dell) on which I'm running the 386 version of FreeBSD 5.4-RELEASE-p5 FreeBSD 5.4-RELEASE-p5 #1: Thu Jul 21 22:30:46 MDT 2005 has a more sane netstat -m: 130 mbufs in use 128/8896 mbuf clusters in use (current/max) 0/177/2480 sfbufs in use (current/peak/max) 288 KBytes allocated to network 0 requests for sfbufs denied 0 requests for sfbufs delayed 208493 requests for I/O initiated by sendfile 26697 calls to protocol drain routines But here's about where any troubleshooting on my own reaches its limit. I noticed that Kris mentioned it was a known problem in the stats counting for SMP machines and had been fixed, but haven't been able to find a reference to that, or any indication of how to do so. Is this fix supposed to have been an accounting bug in the report for netstat, or is it something which would have taken down the machine as has been happening? If switching to single CPU mode works, it's good to hear that I have an option if things continue to act up. But I'd really rather not have to "dumb down" the machine to one CPU when there is the potential of two. Most of the time it's not under a huge load, but periodically there are massive spikes, and that's where having two CPUs really help. If anyone can shed further light on a fix for this problem, it would be greatly appreciated! Dan -- Syzygy Research & Technology Box 83, Legal, AB T0G 1L0 Canada Phone: 780-961-2213
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