Gentoo
First off, if a critical package breaks, it’s nice to have binaries available.
Second off, it seems that passing USE flags at the command prompt is typically non-optimal, as this could have bad interactions with clean or depclean. As such, I try to put all such things in the package.* files.
USE flag descriptions are located here.
gentoolkit
if something goes wrong after upgrading a package/library, it’s possible things need to be rebuilt afterwards. revdep-rebuild provides this functionality. feed it —soname=<library> to make this happen.
ldm2
instructions on its use can be found here. An important step is to remember to add dm-mod to /etc/modules.autoload.d/kernel-2.X for whatever kernel is in use. vgchange -a -y seems to work as far as getting volume groups to emerge from their holes and become visible. There seems to be a lot of magic in here.
md / raid
…must be compiled into the kernel. otherwise, for some reason, the device does not get created by udev. don’t know what the deal is with that. there seemed to be similar udev problems with the nvidia device on push as well…
emerge summary-
emerge -av - ask and be verbose about what’s being merged
emerge -C - remove a package
ebuilds
to make a digest for an ebuild, issue ebuild <file> digest.
equery is your friend. use it.
samba
If you experience client locks in file transfers _only_, try the parameter
use sendfile = no (man smb.conf(5), man sendfile(2))
There also seem some problems with the smbfs implementation of the recent 2.6.x kernels. If you experience problems (lockups) with smbfs, try cifs as an alternative.
There is a good HOWTO about setting up samba3 with cups and clamav at http://www.gentoo.org/doc/en/quick-samba-howto.xml