<html><head></head><body>Microwave!!!<br>
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The EM field from those can cause screens to be wacky, wiggly while they run . I moved my desk from the opposite side of the wall from the home microwave and still had to get 10' away to stop interference.<br>
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Bit flips happen.<br><br><div class="gmail_quote">On March 28, 2016 1:20:45 PM EDT, Todor Fassl <fassl.tod@gmail.com> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<pre class="k9mail"><br />We've run every kind of hardware diagnostic we can think of. Besides, <br />it's just these 14 machines in the 2 shared spaces. Identical machines <br />in private offices don't seem to have any problem.H<br /><br />But, you're right. Ssome kind of power problem is the best theory I've <br />seen for a while. The 2 rooms are in different buildings and they never <br />had a problem before. But maybe somebody is plugging something in. Come <br />to think of it, we had a similar problem years ago when a student put a <br />microwave oven in his office. The computers on the other side of the <br />wall kept going down. I don't know enough about electricity to explain <br />that but the microwave oven and the computer were plugged into outlets <br />on opposite sides of the same wall.<br /><br />What kind of gizmo would a grad student be bringing into a lab that <br />would make linux workstations freeze up?<br /><br />Another reason this theory makes se
nse is
that I haven't gotten a single <br />complaint about the machines going down. You'd think if they were going <br />down while people were using them, I'd get complaints. People are always <br />logged in when they go down but that doesn't mean anything since they <br />tend to walk away w/o logging out. I've looked for patterns in the list <br />of users who were logged in whan a machine went down but didn't see any. <br />I can't rule out that it's somebody doing something though. There might <br />be a pattern and I just didn't see it. But I am sure there isn't one guy <br />who is always logged in whan a machine goes down.<br /><br />On 03/28/2016 11:05 AM, James Taylor wrote:<br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"> The most common, if not the only, reason I've seen partitions get marked read-only is when I've had power glitches that that caused a very brief interruption in connectivity to
the
drives.<br /> Normally that is not an issue with locally attached drives on workstations, but stranger things have happened.<br /> Are the workstations on UPS or is the power to the rooms conditioned properly.<br /> -jt<br /><br /><br /> James Taylor<br /> 678-697-9420<br /> james.taylor@eastcobbgroup.com<br /><br /><br /><br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #8ae234; padding-left: 1ex;"><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #fcaf3e; padding-left: 1ex;"> Todor Fassl <fassl.tod@gmail.com> 3/28/2016 11:54 AM >>><br /></blockquote></blockquote></blockquote> I have a mysterious problem with workstations in a shared use<br /> environment. There are 2 labs in different buildings, onewith 6<br /> workstations and one with 8. These workstations ar
e used
by a group of<br /> about 30 grad student TAs. All are running ubuntu 15.10. Authentication<br /> is via ldap and home directories are mounted via nfs. Every day, 2 or<br /> 3 of the machines go down. The earliest symptom I can find is that the<br /> root filesystem is remounted read-only. Soon they stop responding to<br /> ssh and snmp and they are essentially locked up. They still respond to<br /> pings though.<br /><br /> I've caught the machines in the period where the root system is<br /> read-only but I can still ssh to them. I've found that I cannot nfs<br /> mount home directories on our file server. I can mount nfs shares on<br /> other servers. And I can mount the same home directories if I go to<br /> another workstation. Restarting nfs on the file server has no effect.<br /><br /> When I try to mount a home directory on an effected machine, the mount<br /> just hangs. I ran it with strace and it just showed it was waiting --<br /> for what, I'm not sure and I
don't
have a screen cap available at the<br /> moment. I put a packet sniffer on the server and it showed it received a<br /> single packet from the client and that's it.<br /><br /> There is nothing in the logs on the client. In fact, they simply stop at<br /> some point in the process. At first I attributed this to the root<br /> filesystem being read-only but it continues after I move /var to a<br /> separate file system. At some point it just stops writing records to the<br /> syslog but I don't know if it's before or after the root filesystem is<br /> remounted read-only.<br /><br /> Many of the TAs also have identical workstations in their offices. None<br /> of those machines seem to have this problem. The TAs do tend to walk<br /> away from the workstations w/o logging out. But I wrote a script to kill<br /> off their sessions and it didn't help. I had it send me an email<br /> whenever it killed somebody's session and it doesn't seem to be<br /> correlated with that. In o
ther
words, sometimes machines go down even if<br /> everyone who has used it has remembered to log out.<br /><br /> I'm pretty desperate. Any ideas?<br /><br /><hr /><br /> Ale mailing list<br /> Ale@ale.org<br /> <a href="http://mail.ale.org/mailman/listinfo/ale">http://mail.ale.org/mailman/listinfo/ale</a><br /> See JOBS, ANNOUNCE and SCHOOLS lists at<br /> <a href="http://mail.ale.org/mailman/listinfo">http://mail.ale.org/mailman/listinfo</a><br /><br /><br /><br /><br /><hr /><br /> Ale mailing list<br /> Ale@ale.org<br /> <a href="http://mail.ale.org/mailman/listinfo/ale">http://mail.ale.org/mailman/listinfo/ale</a><br /> See JOBS, ANNOUNCE and SCHOOLS lists at<br /> <a href="http://mail.ale.org/mailman/listinfo">http://mail.ale.org/mailman/listinfo</a></blockquote><br /></pre></blockquote></div><br>
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