Description of problem: In Kdump initramfs, it uses busybox version of cp to save the vmcore to disk. However, it could not handle sparse file. If we could something similar to GNU version of cp's --sparse option, it could be a huge time and disk space saving. For example, in a SGI Altix IA64 machine, it only take 3 minutes and 1.6G disk space for a 123G vmcore using GNU cp. time cp --sparse=always /proc/vmcore vmcore.bcp.sp [root@altix3 ~]# time cp --sparse=always /proc/vmcore vmcore.bcp.sp real 3m1.078s user 0m54.367s sys 1m43.683s [root@altix3 ~]# ls -lh vmcore.bcp.sp -r-------- 1 root root 123G Oct 2 09:45 vmcore.bcp.sp [root@altix3 ~]# du -sh vmcore.bcp.sp 1.6G vmcore.bcp.sp Alternative, we could make busybox to be sparse awareness. It appears Ivana is the RHEL busybox maintainer. Ivana, please let us know if there is a plan to add sparse file support in the near future. Version-Release number of selected component (if applicable): kexec-tools-1.102pre-21.el5 How reproducible: always
you can accomplish the same effect by specifying core_collector as makedumpfile -d 1