Hello, On trečiadienis 02 Birželis 2010 20:14:38 LaMont Jones wrote: > With the introduction of fsync() calls to protect data, applications > that do potentially large apt-get install invocations may not want > to incur the penalty of fsync() calls from dpkg. > > In the case of building a livecd, this can be the difference between > a 10 minute apt invocation, and 21 minutes. > > The use cases where --force-unsafe-io would make sense are those > where apt is modifiying an underlying (possibly empty) base chroot > and the results will be thrown away before the next apt invocation > such that a crash just means "start from the known good base". The > two that jump to mind are: > 1. livecd builds > 2. buildd chroots where we are using lvm snapshots (or pbuilder or > whatever) and will be discarding the resulting chroot upon either > completion or machine reboot). > > Obviously, we want the default to be safe, and the option name to be > scary enough that end users don't think it's a good option to use in > daily life. I spoke with Colin Watson, and he suggested the option > be called --force-unsafe-io. Has there been any progress on this? The problem is that not only dpkg takes longer, but there might be real world costs involved due to this uber-paranoid dpkg behaviour. I've been installing squeeze to microsd card (on guruplug) and debian installer has tortured (literally) my card for 45+ minutes at the stage of unpacking base system. I'm really concerned that at such a pace I will have to throw away my card very soon due to wear level. It does not make much sense for dpkg to be in this uber-paranoid mode at debian-installer time. If power fails, install process will probably have to be started from scratch anyway. What's more, obviously I have no choice to use libeatmydata or similar to fight this dpkg behaviour at debian installer time. In my opinion, dpkg should provide a way to turn off those offensive *sync() calls and debian installer should make use of it. -- Modestas Vainius <modestas@vainius.eu>
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