File system performance

[David Dawes]

In article <1305 at bilver.UUCP> bill at bilver.UUCP (Bill Vermillion) writes:
>In article <1990Nov3.124110.2155 at metro.ucc.su.OZ.AU> dawes at suphys.physics.su.OZ.AU (David Dawes) writes:
>
>>I too am using ESIX rev D with ffs.  One of my file systems became heavily
>>fragmented, and got to the point where there were 0 free blocks, and
>>5000 free frags.  df reported 10000 blocks free, but attempting to write
>>to the file system resulted in "Disk full" errors.  This meant that I
>>had an unusable 5MB on a 65MB file system. (BTW, there were plenty of free
>>inodes.)
> 
>>Is this how FFS is supposed to work, or is there a problem with the ESIX
>>implementation?
>
>That's about the right amount.  Check your manual in the newfs entry or the
>ffsmkfs entry, and you will see that 10% of the disk is reserved and can
>NOT be used by anyone except the super user.  That disk is full 0%, as far
>as a regular user is concerned.

I forgot to mention that I checked this angle, and found that it wasn't the
problem.  I've not seen any evidence that the min-free parameter actually
does anything on an Esix FFS.  My problem was that there were just too many
frags.  I have been able to improve this by using 4k blocks (with 1k frags).

David
--
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 David Dawes (dawes at suphys.physics.su.oz.au) DoD#210   | Phone: +612 692 2639
 School of Physics, University of Sydney, Australia    | Fax:   +612 660 2903
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