Date: Tue, 31 Jan 95 14:54:54 MST From: terry@cs.weber.edu (Terry Lambert) To: alan@picard.isocor.ie (Alan Byrne) Cc: questions@FreeBSD.org, alan@buster.internet-eireann.ie Subject: Re: disk optimization messages from kernel Message-ID: <9501312154.AA28765@cs.weber.edu> In-Reply-To: <Pine.PTX.3.91.950131174611.28887D-100000@picard.isocor.ie> from "Alan Byrne" at Jan 31, 95 05:58:40 pm
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> I've just recentlly upgraded to 2.0R.snap-190128. > I upgraded due to problems with 1.1.5.1 + P90's with PCI cards (long story) > > While I was installing the src distribution in /usr/src I got the > following messages on the console, should I worry about them. > > /usr: optimization changed from TIME to SPACE > /usr: optimization changed from SPACE to TIME > /usr: optimization changed from TIME to SPACE > /usr: optimization changed from SPACE to TIME UFS by default will time-optimize placement of blocks to speed read access. When the disk goes over a certain threshold, it switches from time to space optimization, on the theory that anything that works is better than anything that doesn't -- that is, it is better you don't run out of disk than you be able to read from it as fast as possible. When you drop back below the threshold, plus a watermark, it switches back. Repeating messages like this during an install men that you are close to the watermark and close to the threshold, so you bounce back and forth during the extraction process as it uses then frees large chunks of disk space. It is nothing to worry about; however, if it persists, you will probably want to use the tunefs command to switch over to space permamanently to stop the annoying messages. Practically, this will result in you haveing less frags but sequential access at the ends of large files being slower. There a little more to it than that (clusters will modulate where it hapens -- it isn't only large files), but that's enough to get you to what you need to read to find out more. Terry Lambert terry@cs.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.
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