On 1/5/2012 11:20 AM, m.roth at 5-cent.us wrote: > Billy Davis wrote: >> We are running Centos 5.6. All was fine until yesterday. I attempted >> to tar a 14KB work file to a USB floppy (/dev/sdb) for transport to >> another server. Unfortunately, I keyed in 'tar cvf /dev/sda filename' >> instead of 'tar cvf /dev/sdb filename'. /dev/sda is our main >> (boot/root/apps) scsi hard drive. I realized my mistake, but it was >> too late. The system is still powered up and running, but I am sure >> that I have overlaid (and trashed) the mbr and the disk directory map. > <snip> >> I suspect that when I power the system down, it will not reboot. I can > You have that right. > >> reinstall mbr and grub, but I don't have the original partition table >> start/end values. Since the system is still running, it seems that the >> partition table must still be available to it from somewhere. >> >> Is there any way to easily restore the partition table? > Easily? No (other than the grub-install /dev/sda part). > > Sorry about your problem, but I appreciate the question: it led me to > <http://www.cromwell-intl.com/unix/linux-kernel-details.html>, a fair bit > of which was quite familiar, and other bits weren't. For example, cat > /proc/partitions might give you a serious bit of the information you're > looking for. > > Hope that helps. > > mark > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos > > Thanks Mark. The cat command provided the lost partition information. I used that information with fdisk to restore the partition map. The fdisk partition map is now identical to the cat partition information. Next, I reinstalled grub. All seems normal now, at least until I shutdown and reboot. I'll wait until the weekend to do that, just in case I still have to do a disk restore for some reason. Thanks again for your input. Billy