Red Hat Bugzilla – Bug 465261
[5.3][RFE] Copying of Vmcore Not Sparse Awareness
Last modified: 2008-10-02 10:44:57 EDT
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
[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
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):
you can accomplish the same effect by specifying core_collector as makedumpfile -d 1