By default, current versions of yum delete the
data files and packages that they download, after these have been
successfully used for an operation. This minimizes the amount of
storage space that yum uses. You may enable
caching, so that yum retains the files that it
downloads in cache directories.
Caches provide three advantages:
The performance of
yumincreasesYou may carry out
yumoperations without a network connection, by using only the cachesYou may copy packages from the caches and reuse them elsewhere
By default, yum stores temporary files under
the directory /var/cache/yum/, with one
subdirectory for each configured repository. The
packages/ directory within each repository
directory holds the cached packages. For example, the directory
/var/cache/yum/development/packages/ holds
packages downloaded from the development
repository.
![[Tip]](./stylesheet-images/tip.png) | Clearing the yum Caches |
|---|---|
Cached files use disk space until removed. You may wish to
periodically clear the |
If you remove a package from the cache, you do not affect the copy of the software installed on your system.
To configure yum to retain downloaded files
rather than discarding them, set the
keepcache option in
/etc/yum.conf to 1:
keepcache=1
Refer to Section 9.1, “Editing the yum Configuration” for more
information on editing the yum configuration
file.
Once you enable caching, every yum operation
may download package data from the configured repositories. To
ensure that the caches have a set of package data, carry out an
operation after you enable caching. Use a list
or search query to download package data
without modifying your system.
To carry out a yum command without a network
connection, add the -C option. This causes
yum to proceed without checking any network
repositories, and use only cached files. In this mode,
yum may only install packages that have been
downloaded and cached by a previous operation.
To search for the package tsclient without
using a network connection, enter the command:
su -c 'yum -C list tsclient'
Enter the password for the
root account when
prompted.
![[Note]](./stylesheet-images/note.png) | Cache-only Mode Requires Cached Data |
|---|---|
Cache-only mode requires package data to exist in the caches.
If you enable caching, every |
If you configure it to do so, yum retains the
packages and package data files that it downloads, so that they
may be reused in future operations without being downloaded
again. To purge the package data files, use this command:
su -c 'yum clean headers'
Run this command to remove all of the packages held in the caches:
su -c 'yum clean packages'
When using these commands, at the prompt, enter the password for
the root account.
Purging cached files causes those files to downloaded again the next time that they are required. This increases the amount of time required to complete the operation.