How can "blocks" between packages be resolved?
See the Blocked Packages section in the Gentoo Handbook.
Why is it that emerge does not update all packages?
By default, the dependency graph may not include some packages. For example, it will not include any packages that are listed in the output of emerge --pretend --depclean. It will also not include any build time dependencies for installed packages or binary packages. If you would like to include such build time dependencies even though they are not strictly required, use --with-bdeps=y. You can set EMERGE_DEFAULT_OPTS="--with-bdeps=y" in /etc/make.conf if you would like this option to be enabled by default. If you would like a specific package to be updated in any case, you can use emerge --noreplace <atom> to have it added to the world set.
After running emerge --deep --with-bdeps=y --update world, it is a good idea to use emerge --pretend --depclean to see if there are any packages that it would remove. If that command shows a package that you would like to keep, use emerge --noreplace <atom> to have it added to the world set.
Warning: When you use emerge --depclean to remove unwanted packages, it is a good idea to run revdep-rebuild (from the gentoolkit package) afterwards. |
Note: Run man emerge to view the manual page which documents all emerge options. |
How can I check for reverse dependencies of a package, to know if it can be safely uninstalled?
Run emerge --depclean --pretend --verbose [atom]... to see if there are any reverse dependencies for matched packages.
Warning: When you use emerge --depclean to remove unwanted packages, it is a good idea to run revdep-rebuild (from the gentoolkit package) afterwards. |
Can I mount the portage tree (/usr/portage) via NFS?
It is possible to share the portage tree (/usr/portage) over NFS so that emerge --sync only needs to be run on an NFS server. However, even though NFS clients do not need to run emerge --sync, they must run emerge --metadata each time that the portage tree is updated since otherwise their dependency calculations will slow down due to their metadata cache (located in /var/cache/edb/dep) becoming stale.
Note: NFS clients do not need to run emerge --metadata if they have the metadata_overlay cache module enabled in /etc/portage/modules. The portage manual page (run man portage) describes the steps necessary to enable this. |
Note: With versions of portage >=2.1.5_rc6 there is never any need to run emerge --metadata as long as the user has not enabled FEATURES="metadata-transfer" in make.conf. When metadata-transfer is disabled, metadata cache from the /usr/portage/metadata/cache/ directory will be used directly. Run man make.conf to learn more about metadata-transfer. |
If you encounter problems with an NFS setup it is important that you ensure you have the proper locking daemons on both the NFS client machines and the NFS server machine. Portage uses hardlinks over NFS in an attempt to lock files; if the locking daemon fails to lock files Portage may complain about failed or stale locks. There is a script /usr/lib/portage/bin/clean_locks that can be used to clean out old lockfiles.
Why does the @preserved-rebuild set contain packages that have already been rebuilt?
This is a common problem which indicates that the build system for the given ebuild causes the package to inappropriately link against the old (preserved) version of the library, instead of the new one. As a workaround, you can manually remove the old library (such as libreadline.so.5.2) and then run revdep-rebuild in order to rebuild the packages which linked against it.
As a safety precaution, installation actions for system packages and their deep dependecies are executed only when no other packages are building. This behavior is required in order to avoid cases like bug 256616 (unspecified system dependencies) and bug 259954 (temporarily unsatisfied system dependencies).
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