mjhjmtu

This morning I decided to update my Linux(CentOs 7.2.1511).but yum skip too many package because of dependency problem.

is it OK to proceed to update?! and why yum is skipping that so many packages?!

Transaction Summary
================================================================================
Install 4 Packages (+11 Dependent packages)
Upgrade 160 Packages
Skipped (dependency problems) 941 Packages

Total download size: 195 M

This is because you've not updated the system for long days. Meantime CentOS 7.3 and CentOS 7.4 (current) has been released.

Some packages and libraries has been obsoleted in new system. To update yum need to remove them. But as your system is running based on those yum is failed to remove those packages.

Solution dnf can solve and skipe some dependency issues automatically. Install dnf as follows

sudo yum install dnf

If this fails with 'No Package foundinstalldnffrom somerpmsource. Google for 'dnf rpm download, chose one for CentOS 7.x or RHEL 7. Then install it as follows

sudo rpm -Uvh path_to_downloaded_rpm

Then Update using dnf as follows
sudo dnf update

Then clean as much unnecessary packages as possible using

sudo yum autoremove
sudo yum clean all
sudo dnf autoremove
sudo dnf clean all

Now again try to update using yum. You're likely to hit dependency problem again but with lesser number of package having issues. Then try to understand what those packages are and remove them one by one using yum or dnf.

Warning Please have a full backup before doing anything. It's very much likely that you'll face some issues during the process. Please update with error messages.