Date: Wed, 10 Mar 2004 16:09:05 -0500 From: "Brian F. Feldman" <green@FreeBSD.org> To: Poul-Henning Kamp <phk@FreeBSD.org> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/sys mdioctl.h src/sys/dev/md md.c src/sbin/mdconfig mdconfig.8 mdconfig.c Message-ID: <200403102109.i2AL96dn073169@green.homeunix.org> In-Reply-To: Message from Poul-Henning Kamp <phk@FreeBSD.org> <200403102041.i2AKf90l061660@repoman.freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
Poul-Henning Kamp <phk@FreeBSD.org> wrote: > In addition to more closely emulating a real disk device with a > non-lying write-cache, this makes the writes exempt from rate-limited > (there to avoid starving the buffer cache) and consequently prevents > the deadlock. > > Unfortunately performance takes a hit. > > Add "async" option to give people who know what they are doing the > old behaviour. Could you please implement an errx(3) for MD_ASYNC without MD_FORCE, or something of that ilk? Users who use anything other than mdconfig(8) for leanring how to use mdconfig(8) could quite easily run across something like: "Make sure to use -o async to get better performance." and shoot themselves in the foot, whereas if they saw: "Make sure to use -o force -o async..." or "Make sure to use -o (dangerous|unsafe|deadlock_prone)_async..." they would be better aware of the risks. Just changing the option to make it obvious to the user that the option is not just asynchronous but also dangerous moves the warning documentation to a more visible location. This is tools, not policy, but anything that, at little cost, increases anti-foot-shooting capabilities of the tools is a Good Thing, IMHO. -- Brian Fundakowski Feldman \'[ FreeBSD ]''''''''''\ <> green@FreeBSD.org \ The Power to Serve! \ Opinions expressed are my own. \,,,,,,,,,,,,,,,,,,,,,,\
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200403102109.i2AL96dn073169>