axelget, yum and crccheck failed

Question

I want to increase my download speed with yum and finally found a solution (axelget) that works fine at the beginning. But after one time work, I get an error and I cannot use it any more because of "crc" problem!

[root@dhcppc0 ali]# yum update -y
Loaded plugins: axelget, fastestmirror, langpacks, presto, refresh-packagekit
No metadata available for fedora
No metadata available for google-chrome
No metadata available for rpmfusion-free
No metadata available for rpmfusion-free-updates
No metadata available for rpmfusion-nonfree
No metadata available for rpmfusion-nonfree-updates
No metadata available for updates
Finish Download MetaData of Enabled Repo
Loading mirror speeds from cached hostfile
 * fedora: www.ftp.ne.jp
 * rpmfusion-free: mirror.nexcess.net
 * rpmfusion-free-updates: mirror.nexcess.net
 * rpmfusion-nonfree: mirror.nexcess.net
 * rpmfusion-nonfree-updates: mirror.nexcess.net
 * updates: www.ftp.ne.jp
Resolving Dependencies
...
Upgrade  11 Packages
Total download size: 6.8 M
Downloading Packages:

CRC check failed 0x84dd7640 != 0xbf02314L

Here is another log :

[root@dhcppc0 ali]# yum install axel
Loaded plugins: axelget, fastestmirror, langpacks, presto, refresh-packagekit
fedora/18/x86_64/metalink                                                             | 9.7 kB  00:00:00     
google-chrome                                                                         |  951 B  00:00:00     
rpmfusion-free                                                                        | 3.3 kB  00:00:00     
rpmfusion-free-updates                                                                | 3.3 kB  00:00:00     
rpmfusion-nonfree                                                                     | 3.3 kB  00:00:00     
rpmfusion-nonfree-updates                                                             | 3.3 kB  00:00:00     
updates/18/x86_64/metalink                                                            | 5.7 kB  00:00:00     
(1/2): rpmfusion-nonfree-updates/primary_db                                           | 133 kB  00:00:04     
(2/2): rpmfusion-free-updates/primary_db                                              | 329 kB  00:00:12     
repomd.xml                                                                            | 4.2 kB  00:00:00     
Initializing download: tp://ftp.riken.jp/Linux/fedora/releases/18/Everything/x86_64/os/repodata/7606e9d3ed634ddab6e4f2317fe2b647f7f20f00cc183613338d3929e2c4ccc0-prestodelta.xml.gz
File size: 1574148 bytes
Opening output file /var/cache/yum/x86_64/18/fedora/7606e9d3ed634ddab6e4f2317fe2b647f7f20f00cc183613338d3929e2c4ccc0-prestodelta.xml.gz
Starting download

Connection 0 finished                                                          ]
Connection 3 finished                                                          ]
Connection 1 finished                                                          ]
Connection 2 finished                                                          ]
[100%] [..................................................] [  43.5KB/s] [00:00]

Downloaded 1537.3 kilobytes in 35 seconds. (43.54 KB/s)
update fedora metadata sucessfully
repomd.xml                                                                            |  951 B  00:00:00     
update google-chrome metadata sucessfully
repomd.xml                                                                            | 3.3 kB  00:00:00     
update rpmfusion-free metadata sucessfully
repomd.xml                                                                            | 3.3 kB  00:00:00     
update rpmfusion-free-updates metadata sucessfully
repomd.xml                                                                            | 3.3 kB  00:00:00     
update rpmfusion-nonfree metadata sucessfully
repomd.xml                                                                            | 3.3 kB  00:00:00     
update rpmfusion-nonfree-updates metadata sucessfully
repomd.xml                                                                            | 4.7 kB  00:00:00     
Initializing download: tp://ftp.riken.jp/Linux/fedora/updates/18/x86_64/repodata/1767a570ae94a2e780bc276e5e0afb66788e1ac1e296d93e8292c593ccc39856-prestodelta.xml.gz
File size: 2301411 bytes
Opening output file /var/cache/yum/x86_64/18/updates/1767a570ae94a2e780bc276e5e0afb66788e1ac1e296d93e8292c593ccc39856-prestodelta.xml.gz
Starting download

Connection 3 finished                                                          ]
Connection 2 finished                                                          ]
Connection 1 finished                                                          ]
Connection 0 finished                                                          ]
[100%] [..................................................] [  37.2KB/s] [00:00]

Downloaded 2247.5 kilobytes in 1:00 seconds. (37.19 KB/s)
update updates metadata sucessfully
Finish Download MetaData of Enabled Repo
Loading mirror speeds from cached hostfile
 * fedora: ftp.riken.jp
 * rpmfusion-free: mirror.liberty.edu
 * rpmfusion-free-updates: mirror.liberty.edu
 * rpmfusion-nonfree: mirror.liberty.edu
 * rpmfusion-nonfree-updates: mirror.liberty.edu
 * updates: ftp.riken.jp
Package axel-2.4-7.fc18.x86_64 already installed and latest version
Nothing to do
[root@dhcppc0 ali]# yum update -y
Loaded plugins: axelget, fastestmirror, langpacks, presto, refresh-packagekit
No metadata available for fedora
No metadata available for google-chrome
No metadata available for rpmfusion-free
No metadata available for rpmfusion-free-updates
No metadata available for rpmfusion-nonfree
No metadata available for rpmfusion-nonfree-updates
No metadata available for updates
Finish Download MetaData of Enabled Repo
Loading mirror speeds from cached hostfile
 * fedora: ftp.kddilabs.jp
 * rpmfusion-free: mirror.nexcess.net
 * rpmfusion-free-updates: mirror.nexcess.net
 * rpmfusion-nonfree: mirror.nexcess.net
 * rpmfusion-nonfree-updates: mirror.nexcess.net
 * updates: ftp.kddilabs.jp
Resolving Dependencies
--> Running transaction check
...
Upgrade  11 Packages

Total download size: 6.8 M
Downloading Packages:


CRC check failed 0x84dd7640 != 0xbf02314L

What is "crc" and how can this problem be solved?

Installed Packages:

Name : axel
Arch : x86_64
Version : 2.4
Release : 7.fc18

This is on Fedora 18

Edit (My solution) :

run this commands :

yum clean expire-cache
yum clean dbcache

then disable fastestmirror plugin and update your cache(yum update). now install some package and see if use axelget for downloading, active fastestmirror .

Answer 1

CRC stands for a Cycle Redundancy Check. It's a method to make sure that the data being sent is received correctly. Basically it makes sure that if i sent you the bits "1001001" you received "1001001".

Read more about them on the wikipedia page: Cyclic redundancy check.

Things to try #1

I would try changing which mirrors you're using. I have a feeling that your problem isn't on your end at all. It might be with one of the mirrors.

You can try a couple of these commands to see if it clears up your problem.

yum clean expire-cache
yum clean dbcache

Or you can just clean everything:

yum clean all

Things to try #2

At this point if the CRC error is still persisting then there are still 2 areas of concern that we need to eliminate:

1. Is it a network/hardware issue local to the box?
2. Is the package on one of the repos corrupt?

I would eliminate the package first by using yumdownloader to download the packages like so:

yumdownloader axelget

Once the RPM's been downloaded you can either try to get yum to do a local install:

yum localinstall <axelget rpm>

or use rpm directly:

rpm -ivh <axelget rpm>

Issues with yum-plugin-fastestmirror

From time to time this plugin has caused issues with my being able to update. It either will be pointing to a mirror who's offering packages inconsistent with other mirrors or the mirror itself is extremely slow. The slow issue will eventually work itself out but if you're inpatient you can do the following:

rm -f /var/cache/yum/timedhosts.txt

This will clear out the times for the different mirroring servers and allow the times to be re-collected. Often this is enough to clear up any mirror problems.

If you continue to have issues with a specific mirror, you can do the following to exclude them. In the config file for the fastestmirror plugin, /etc/yum/pluginconf.d/fastestmirror.conf:

[main]
verbose = 0
socket_timeout = 3
enabled = 1
hostfilepath = /var/cache/yum/timedhosts.txt
maxhostfileage = 1
exclude = some-mirror.com, other-junk-mirror.com

The above changes takes place immediately the next time you run yum.

If neither of the above fix a problem that seems related to a the mirror providing a package you can always disable the plugin through its config file: /etc/yum/pluginconf.d/fastestmirror:

# enabled
# enabled=1

# disabled
enabled=0