From owner-freebsd-hackers Tue Oct 2 8:59:57 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from galileo.poli.hu (galileo.poli.hu [193.224.190.1]) by hub.freebsd.org (Postfix) with ESMTP id BA4CE37B40A for ; Tue, 2 Oct 2001 08:59:53 -0700 (PDT) Received: from faber.poli.hu (mail@faber.poli.hu [193.224.190.2]) by galileo.poli.hu (8.11.3/8.11.3) with ESMTP id f92FxoA25100 for ; Tue, 2 Oct 2001 17:59:50 +0200 (CEST) (envelope-from mauzi@faber.poli.hu) Received: from mauzi (helo=localhost) by faber.poli.hu with local-esmtp (Exim 3.22 #1 (Debian)) id 15oRxU-0006fS-00 for ; Tue, 02 Oct 2001 17:59:48 +0200 Date: Tue, 2 Oct 2001 17:59:48 +0200 (CEST) From: Egervary Gergely To: Subject: newbie question: filesystem i/o Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG hi hackers, I'm quite new to FreeBSD but not in UN*X, please let me ask a question: I wonder that the filesystem performance under FreeBSD is so great. I'm doing disk-to-disk file copies, like ``dd if=file1 of=file2 bs=64k'' and the performance is much better than on other unices. Other systems use 16k or 64k (or whatever MAXBSIZE is set to) chunks for sequential i/o, and the disk seeks like an evil. On FreeBSD, the disk seeks _much_ less. probably FreeBSD is re-blocking the (contigous?) chunks, and does i/o with huge blocks like several megabytes? How is it done technically? Is it the filesystem, or the VM? could someone enlighten me please? :) cheers, -- mauzi To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message