The company i worked for is running IBM System Storage SAN Volume Controller (SVC) to hold some of the media content. SATA disks are attached to the server via fiber channel protocol. One night i saw input output error on one of the disks in a linux box. Then i asked for storage admin to analyze it. When creating a volume on the SVC there is an option for thin provisioning. It allocates disk blocks to the volume as needed. Storage Admin realized that disk pool for thin provisioning was full. Then he gives extra disks to the pool and free up some space. But this was not happened at once. Storage admin had to repair the disk that gave IO error. Because the disk had fallen into offline status. After a long repair process disk status changed into online. It was not realized by the linux server even after rescan commands. The server had to be rebooted. After all these operations disk was ready.
After registering redhat linux system for rhn, yum update command returned "No Packages marked for Update" # yum updateLoaded plugins: downloadonly, securitySetting up Update ProcessNo Packages marked for Update