From owner-freebsd-questions Tue Jan 1 8:34: 3 2002 Delivered-To: freebsd-questions@freebsd.org Received: from mustard.heime.net (mustard.heime.net [194.234.65.222]) by hub.freebsd.org (Postfix) with ESMTP id C491E37B41E for ; Tue, 1 Jan 2002 08:34:00 -0800 (PST) Received: from localhost (roy@localhost) by mustard.heime.net (8.11.6/8.9.3) with ESMTP id g01GXtf07752; Tue, 1 Jan 2002 17:33:56 +0100 Date: Tue, 1 Jan 2002 17:33:55 +0100 (CET) From: Roy Sigurd Karlsbakk X-Sender: To: Dan Nelson Cc: Subject: Re: increasing readahead? In-Reply-To: <20011219200649.GA30574@dan.emsphone.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Wed, 19 Dec 2001, Dan Nelson wrote: > In the last episode (Dec 19), Roy Sigurd Karlsbakk said: > > I really need a LARGE readahead for my application. Does anyone know > > how I can increase the current one? > > man setvbuf > > > I also need a way to pre-allocate chunks of 4 megs when I'm writing > > to a file, to make the actual fragments large enough to eliminate a > > large part of the actual overhead of seeking > > Are you sure this is your problem? FreeBSD does write clustering and > allocates disk space to avoid fragmentation. Do you know how large these clusters are? Are there any way of monitoring / controlling these? roy -- Roy Sigurd Karlsbakk, MCSE, MCNE, CLS, LCA Computers are like air conditioners. They stop working when you open Windows. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message