Date: Sun, 30 Sep 2001 18:52:12 +0100 From: Ian Dowse <iedowse@maths.tcd.ie> To: Cy Schubert - ITSD Open Systems Group <Cy.Schubert@uumail.gov.bc.ca> Cc: Mike Harding <mvh@ix.netcom.com>, admin@rshb.com.ru, stable@FreeBSD.ORG Subject: Re: dirpref gives massive performance boost Message-ID: <200109301852.aa80614@salmon.maths.tcd.ie> In-Reply-To: Your message of "Sun, 30 Sep 2001 09:50:39 PDT." <200109301651.f8UGpFs02421@cwsys.cwsent.com>
next in thread | previous in thread | raw e-mail | index | archive | help
In message <200109301651.f8UGpFs02421@cwsys.cwsent.com>, Cy Schubert - ITSD Ope n Systems Group writes: >In message <20010930162030.10A5B133C1@netcom1.netcom.com>, Mike Harding >writes: >> So it sounds like there would be some benefit in tar'ing and untarring >> /usr/local, /usr/ports, /usr/src, etc. which will be less >> disruptive... > >At work, I don't have the luxury of doing a wholesale conversion as all >the machines have one disk and most have only one partition. I've been >toying with the idea of duplicating up /bin for example to /bin.new, It is on directory hierarchies such as /usr/ports and /usr/src where there are a large number of "associated" directories that the biggest performance improvements are to be made. This is especially true when the hierarchy takes up only a small proportion of the whole partition. Before the dirpref changes, files were generally allocated physically close to their parent directory, but directories were spread out randomly across the filesystem. The dirpref changes make it much more likely for directories to be located close to their parent directory too. For /usr/ports, this is a huge win - before these changes, a port's main directory and its 'files' subdirectory were located on average a third of the filesystem size away from each other (I think). Now they are likely to be just a few blocks away, maybe even waiting in the disk's cache. Since these improvements are all about the placing of subdirectories, there isn't much point in re-creating flat directories such as /bin, /usr/bin etc. For /usr/local, it might only be worthwhile re-creating some application directories that have a huge number of subdirectories. However, a system with a large number of user home directories might see a big improvement if /home was rebuilt, because all of a user's files would end up much closer together on the disk. Ian To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi? <200109301852.aa80614>