UNIX 4.2 thrashing - the cause?

[John Nelson]

In article <1608 at ittvax.UUCP> long at 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)