> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Anthony > Atkielski > Sent: Sunday, February 06, 2005 3:25 AM > To: freebsd-questions@freebsd.org > Subject: Re: Leaving a Computer Running ? > > > Ted Mittelstaedt writes: > > TM> In a clean room or positive pressure network room, where there is > TM> an extremely low level of dust, off-the-shelf computer fans will > TM> last many years longer than fans in a typical home PC. > > What about filters?
HEPA-quality required. On my current FreeBSD server (not in a clean room, > alas!), the fans that I installed have washable plastic filters, which > removes part of the dust. Worthless for this kind of problem. The particles that are the problem go right through these. I'd love to find disposable filters that > capture more dust and can simply be tossed at regular intervals. > Ideally, they wouldn't interfere with airflow too much, but I realize > that catching all dust and maintaining airflow are almost mutually > exclusive. > You just put in a bigger filter and more fans for that problem. What are needed are better fans. The old VAX/VMS systems had fans that ran perfectly balanced, forever, even when coated with crud. > Currently I have two 8-cm fans blowing directly past the disk > drives, in > order to keep them as cool as possible (not that the drives are that > busy, but I'm trying to be prudent). > > TM> For PC's left on for long periods, they have a different problem > TM> because disk drives that spin at full speed continuiously (as > TM> server drives do, servers have power saving disabled on their > TM> drives of course for obvious reasons) the disk will eventually > TM> overheat in just about all the garden-variety case designs. > TM> (you can fix this yourself of course, by adding more fans to > TM> the cases) Once the drive overheats the lubrication migrates > TM> out of the bearings and if the drive is turned off for more > TM> than 6-8 hours, it cools down enough to the point that the drive > TM> will never spin up again. > > Interesting! Have you actually had this happen? Yes, about 6 times over the last 10 years. All of it was crap small minitowers or otherwise airflow-restricted cases that let the drive heat up too hot to touch. Sometimes hitting it with a hammer - hard - right when you apply power will get them going again. I've had drives fail > on restart but not because they wouldn't spin up (as far as I know). > > I've had drives fail very quickly when I've packed too many of > them into > a single case (as in weeks or months). We needed the additional space > and we were lucky to get the drives--asking for more fans or a better > case or anything like that would have been an exercise in futility. > Yup, happens all the time. You needed a Go Big Red Fan for that situation. (read Neal Stephenson's The Big U for an explanation) Ted _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
