Date: Sat, 7 Feb 2004 15:37:08 +0100 From: Harald Schmalzbauer <h@schmalzbauer.de> To: Erik Trulsson <ertr1013@student.uu.se>, Stijn Hoop <stijn@win.tue.nl> Cc: freebsd-current@freebsd.org Subject: Re: Reserved space (WAS: How to calculate bsdlabel size) Message-ID: <200402071537.16757@harrymail> In-Reply-To: <20040207141103.GA65140@falcon.midgard.homeip.net> References: <20040206072244.GT908@cirb503493.alcatel.com.au> <20040207131735.GA2803@pcwin002.win.tue.nl> <20040207141103.GA65140@falcon.midgard.homeip.net>
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--Boundary-02=_cgPJA3bWjJHcuYi Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: quoted-printable Content-Description: signed data Content-Disposition: inline On Saturday 07 February 2004 15:11, Erik Trulsson wrote: > On Sat, Feb 07, 2004 at 02:17:35PM +0100, Stijn Hoop wrote: > > On Fri, Feb 06, 2004 at 01:57:11PM -0500, Garrett Wollman wrote: > > > <<On Fri, 6 Feb 2004 09:44:58 +0100 (CET),=20 =3D?iso-8859-1?q?Claus=3D20Guttesen?=3D <cguttesen@yahoo.dk> said: > > > > Does the algorithm(s) rely only on percentage of free > > > > space? On a five TB (netto) filesystem eigth percent > > > > is approx. 410 GB which seems quite alot. > > > > > > A good Data Structures text will prove to you that the efficiency of > > > hashing algorithms of the sort that the UFS block allocator uses > > > depends only on the occupancy ratio and not on the absolute number of > > > free hash slots. > > > > Which translates into what wrt this question? That the 8% of free space > > is really necessary for the UFS block allocator to function efficiently? > > Yes, that is exactly what it translates to. Hm, I don't really understand why, but anyway, what performance degradation= do=20 I have to expect when lowering it to 2%? =2DHarry --Boundary-02=_cgPJA3bWjJHcuYi Content-Type: application/pgp-signature Content-Description: signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (FreeBSD) iD8DBQBAJPgcBylq0S4AzzwRAruLAJ9KCHHucTwkysriaXEhN0FVttEcwACePUMU AfyhWvQoGxDUtTausLlWgbM= =NJlZ -----END PGP SIGNATURE----- --Boundary-02=_cgPJA3bWjJHcuYi--
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