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Date:      16 Oct 2001 12:11:29 -0400
From:      Randell Jesup <>
To:        Matt Dillon <>
Cc:        "David O'Brien" <obrien@FreeBSD.ORG>, cvs-committers@FreeBSD.ORG, freebsd-arch@FreeBSD.ORG
Subject:   Re: cvs commit: src/sbin/newfs newfs.8 newfs.c
Message-ID:  <0000156d03191407d1@[]>
In-Reply-To: Matt Dillon's message of "Sun, 14 Oct 2001 19:56:53 -0700 (PDT)"
References:  <><><><><><><><00005ba2015f4b07d1@[]>

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Matt Dillon <> writes:
>:> It has been said in the lists many times that 16k/2k is more efficient
>:> (and I'm using it myself by defautl now).

>    You can use 16K/2K safely.  Anything larger may fragment the buffer
>    cache's KVA space and create issues.  There are no known bugs (other
>    then fragmentation), but people have sporatically reported weirdness
>    with other combinations.  There have been no solid bug reports.

From disklabel.c after my mods from a year or so ago:
(these are for >1GB partitions)

#define BIG_NEWFS_BLOCK  16384U
#define BIG_NEWFS_FRAG   4096U
#define BIG_NEWFS_CPG    64U

You (and others) passed on these patches; the 16k/4k/64 values I took
(except for cpg) from the CVS log for /usr/src/release/sysinstall/install.c=

(now in Attic).

: Revision 1.244 Thu Aug 5 19:50:25 1999 UTC (2 years, 2 months ago) by phk=

: Make the newfs parameters a global option.
: The default is still "-b 8192 -f 1024" but my experiments show that
: "-b 16384 -f 4096 -c 100" is a more sensible value for modern
: disksizes.

So, do we really have problems with 16k/4k/64?  If so, let's fix the proble=
Or should we reduce the defaults to 16k/2k?  If so, what about existing
FS's with these values?  If values above that are broken, should we
disable them in newfs, or at least print a warning?

Randell Jesup, Worldgate Communications, ex-Scala, ex-Amiga OS team
"They that can give up essential liberty to obtain a little temporary safet=
 deserve neither liberty nor safety." 
              -Benjamin Franklin, Historical Review of Pennsylvania, 1759.

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