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From: rogerk@MIPS.com (Roger B.A. Klorese)
Newsgroups: comp.sys.mips
Subject: Re: Miscellaneous questions
Keywords: Diskspace, newfs.ffs, mount
Message-ID: <439@spim.mips.COM>
Date: 7 Jan 91 17:21:31 GMT
References: <1991Jan7.160027.5883@athena.mit.edu>
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Organization: MIPS Computer Systems, Inc., Sunnyvale, CA
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In article <1991Jan7.160027.5883@athena.mit.edu> glee@athena.mit.edu (Gilbert Huppert) writes:
>Question #1:  How do I access the full potential of the disk?

Well, it's not clear what the full capacity really is, Gil.  When disk
marketeers talk about megabytes, they talk about thousand-bytes, not 
1024-bytes, so there's a loss right there.  Additionally, the FFS structure,
inode table, superblocks, etc. do eat a good bit of space.

>Question #2:  Is there anyway the minimize the reserved disk overhead?

Actually, the 10% is not reserved to minimize crashes, but because the
cylinder-block allocation algorithm gets messy on very full disks.  You
can tune the threshhold for a partition down from 10% with /etc/tunefs.ffs:

	/etc/tunefs.ffs -m 3 /dev/rdsk/isc0d1s2

would drop it to 3%.  (You would need to do this on an unmounted filesystem,
or tune, unmount, and remount, for it to be seen.)

>Question #3:  Any ideas why I might not be able to mount a free filesystem?

Be certain that no partitions in use overlap your problem partition.
-- 
ROGER B.A. KLORESE                                  MIPS Computer Systems, Inc.
MS 6-05    930 DeGuigne Dr.   Sunnyvale, CA  94086              +1 408 524-7421
rogerk@mips.COM         {ames,decwrl,pyramid}!mips!rogerk         "I'm the NLA"
"The problem with the rat race is even if you win you're still a rat." - Tomlin