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Posting-Version: version B 2.10.2 9/3/84; site genrad.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!genrad!john
From: john@genrad.UUCP (John Nelson)
Newsgroups: net.unix-wizards
Subject: Re: UNIX 4.2 thrashing - the cause?
Message-ID: <639@genrad.UUCP>
Date: Tue, 22-Jan-85 08:48:18 EST
Article-I.D.: genrad.639
Posted: Tue Jan 22 08:48:18 1985
Date-Received: Sun, 27-Jan-85 04:40:09 EST
References: <1282@kaist.UUCP> <1608@ittvax.UUCP>
Reply-To: john@genrad.UUCP (John Nelson)
Organization: GenRad, Inc., Bolton, Mass.
Lines: 18

In article <1608@ittvax.UUCP> long@ittvax.UUCP (H. Morrow Long [Systems Center]) writes:
>> Filesystem    kbytes    used   avail capacity  Mounted on
>> /dev/hp0a       7421    6519     159    98%    /
>> /dev/hp1h     137616  120835    3019    98%    /usr
>> /dev/hp1g      74691   65354    1868    97%    /usr/spool
>> /dev/hp2h     137616  120775    3079    98%    /va <- user area
>> /dev/hp0g      38639   34747      28   100%    /vb <- user area
>> -- 
>	The transfer rates to be given in section 4 were
>	measured on file systems kept less than 90% full.  If the reserve of
>	free blocks is set to zero, the file system throughput rate tends to be
>	cut in half, because of the inability of the file system to localize
>	the blocks in a file.

I think that you missed the fact that the available free space reported by
4.2 df ALREADY TAKES the 10% into account when reporting available blocks
and capacity used.  Note that on the 100% segment kbytes != used.  This
10% is not hardwired, and is settable by tunefs(8)