From owner-freebsd-arch Fri Mar 30 12:34:11 2001 Delivered-To: freebsd-arch@freebsd.org Received: from mail.wgate.com (mail.wgate.com [38.219.83.4]) by hub.freebsd.org (Postfix) with ESMTP id A814037B71A for ; Fri, 30 Mar 2001 12:34:08 -0800 (PST) (envelope-from rjesup@wgate.com) Received: from jesup.eng.tvol.net ([10.32.2.26]) by mail.wgate.com with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2653.13) id H70XLHVH; Fri, 30 Mar 2001 15:34:01 -0500 Reply-To: Randell Jesup To: Bakul Shah Cc: Kirk McKusick , arch@FreeBSD.ORG Subject: Re: Background Fsck References: <200103301753.MAA03709@valiant.cnchost.com> From: Randell Jesup Date: 30 Mar 2001 15:36:18 -0500 In-Reply-To: Bakul Shah's message of "Fri, 30 Mar 2001 09:53:06 -0800" Message-ID: User-Agent: Gnus/5.0807 (Gnus v5.8.7) Emacs/20.7 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Bakul Shah writes: >But like Terry I worry about disks write errors or blocks >going bad. And not knowing how well the bg fsck (or for that >matter soft-updates) copes with that gives me an uneasy >feeling. Perhaps bg fsck should not do anything if it >discovers structural inconsistency? This worries me too. However, "not doing anything" can be a problem if the system isn't being actively monitored. >I know I don't have to run it if I feel this way but the >point is to understand the behavior. Yes. >> Many improvements have been made to fsck over the years. Through >> there are undoubtedly more that could be made, there are no big >> easy improvements left. > >I was less than clear; what I was asking is if anyone has >looked at whether the fsck *algorithm* is optimal. I >wondered about its complexity -- is it O(n^2) or O(n log n) >or something else and whether it is the best possible >algorithm. Also think about the memory usage requirements. FS checkers on big drives can be memory hogs; I don't know about fsck. I'm guessing that it's O(n) so long as you don't run over memory requirements, but that could easily happen. -- Randell Jesup, Worldgate Communications, ex-Scala, ex-Amiga OS team ('88-94) rjesup@wgate.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message