Date: Thu, 18 Oct 2001 20:06:34 +0200 (CEST) From: Oliver Fromme <olli@secnetix.de> To: freebsd-stable@FreeBSD.ORG Subject: Re: dirpref gives massive performance boost Message-ID: <200110181806.f9II6Yn92967@lurza.secnetix.de> In-Reply-To: <01d101c157fb$1fab1c80$fe0c4042@inethouston.net>
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David W. Chapman Jr. <dwcjr@inethouston.net> wrote: > And that's exactly what I'm trying to figure out. Did I build my kernel > with then capability and then newfs my drive, or did I newfs my drive before > this capability. The answer is simple: It doesn't matter at all. The presence of the dirprefs code in the kernel has NO influence on newfs at all. Read my lips: newfs does NOT enable dirprefs. There is nothing in particular that enables dirprefs. It's not a flag or anything. When you're using a new kernel with the dirprefs code, it's in effect immediately, whether you newfs your filesystems or not. The point is just that the best improvement is achieved when you empty your filesystems and restore them. "rm -rf" will do, but newfs is simply faster. The diprefs code changes the way directories are laid out on the disk when you _create_ them. Therefore, it does not improve preformance on old directories which existed before the dirprefs code went into the kernel. It only affects directories created with the dirprefs code. That's why people recommend to newfs and restore your filesystems: in order to give the dirprefs code (in the kernel) a chance to do its work on the whole filesystem. It is NOT the newfs program that does any magic. It does NOT make a difference whether you newfs'ed the filesystem with or without the dirprefs code. The resulting (empty) filesystem looks exactly the same. But when you restore the data from your backup (WITH the dirprefs code in effect), the directories will end up on different places on the disk. I hope I made myself clear this time. :-) Regards Oliver -- Oliver Fromme, secnetix GmbH & Co KG, Oettingenstr. 2, 80538 München Any opinions expressed in this message may be personal to the author and may not necessarily reflect the opinions of secnetix in any way. "All that we see or seem is just a dream within a dream" (E. A. Poe) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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