Yum is a dog to run on older systems with small amounts of memory, or when you run a VPS (virtual private server) that does not have much memory. When running a yum update, you get errors such as memory alloc (8 bytes) returned NULL. Recommendations are:
But ofthen that's not enough. A simple yum update can find a huge number of packages to update and nothing will help you getting the required amount of free memory. You can work around this problem by updating them one-by-one.
First generate a list of packages-to-be-updated, then dump them in a file.
$ yum -q check-update | cut -f1 -d" " > list
Now use a loop that runs yum for each package listed in the file:
$ for i in $(cat list); do sudo yum -y update "$i"; done