Date: Thu, 24 Sep 1998 12:50:50 +0200 (CEST) From: Konrad Heuer <kheuer@gwdu60.gwdg.de> To: Peter Kok <peter@sweda.com.hk> Cc: freebsd <freebsd-questions@FreeBSD.ORG> Subject: Re: fragmentation Message-ID: <Pine.BSF.3.96.980924123624.801A-100000@gwdu60.gwdg.de> In-Reply-To: <3609F91C.A4362BE5@sweda.com.hk>
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On Thu, 24 Sep 1998, Peter Kok wrote: > After boot up a computer, there is message prompted > > /dev/rmd0s2a: clean, 17705 free (313 frags, 2174 blocks, 1.0 > fragmentation) > > what is the meaning of frags? and how do you do defragmentation? You don't need to defragment a FreeBSD file system (which is essentially a 4.2BSD fast file system (ffs)). The file system typically uses 8K blocks of disk space. Since files are often smaller a file can use fragments (typically 1K) of a block. To be more precise, the last block of a file may be fragmented. Fragmentation you probably think of is spreading all the blocks of a file over the disk. The Berkeley ffs implements very intelligent algorithms to prevent this and to optimize file system throughput. Take a look at the system documentation: gunzip < /usr/share/doc/smm/05.fastfs/paper.ascii.gz | more Regards Konrad Heuer // Gesellschaft fuer wissenschaftliche Datenverarbeitung mbH // Goettingen (GWDG), Am Fassberg, D-37077 Goettingen, Germany // // kheuer@gwdu60.gwdg.de To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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