More Info on Reserved Filesystem Space

Date: Fri Nov 01 1996 - 13:17:03 CST

I've gotten some questions regarding my summary, so I've decided to post
some of the relevant responses here:

>From Fri Nov 1 14:13:06 1996
Date: Thu, 31 Oct 1996 13:30:29 -0700 (MST)
From: Ric Anderson <>
Subject: Re: I know I saw this explained before, but...

df reports kbytes (the total size) which is usually bigger than
avail+used. This is because of the minfree setting of newfs
which defaults to 10%, meaning the last 10% of the disk can only
be used by uid 0. I've dropped this down as low as 2% on
large partitions with no problems. Just keep about 20mb or so

Allegedly there is a huger performance hit from doing this, but
I haven't seen any evidence of it. To change the value after
newfs, use tunefs on a dismounted raw filesystem, like
        tunefs -m 3 /dev/rdsk/c0t0d0s4
Ric (<> "Ric Anderson", using RTD's public internet access)

>From Fri Nov 1 14:14:52 1996
Date: Thu, 31 Oct 1996 15:12:31 -0500 (EST)
Subject: Re: I know I saw this explained before, but...


df tell you how much diskspace is available for users, there is around a
10% overhead that only root can use (in case the partition becomes completely
full, root can still do stuff like compress files) ... you can tune
the amount of overhead with 'tunefs'


And I also had several polite references to the man pages for df and

Hope this cleared up any questions,


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