On 2010-06-29 19:44, Eberhard Moenkeberg wrote: > On Tue, 29 Jun 2010, J. Epperson wrote: >> Arrived home very tired and in a lapse of judgement tried to configure a >> new USB backup drive on my PERC3 based home server, with a new cat roaming >> between me and the monitor. Created a new partition on the existing >> /dev/sda instead of the new /dev/sdb. System is still running, and I"m >> doing an rsync to the new drive now. >> >> Can some kind soul help me remember how to repair this surgically instead >> of rebuilding the filesystem and reloading it? If not, I deserve it. > > You just need to revert the partition table change. > If you do not have a backup of the master boot record (LILO would have > one), you can use the df output to estimate the right cylinder numbers.
/proc/partitions is possibly a better reference. > If you need trial and error to find the boundaries, "tune2fs -l /dev/sdaX" > is a non-destructive test. Doubtful that will work; it will refer to the old partition table the kernel is still using. You should be able to use dmsetup to create device nodes with offset into /dev/sda if you want to do this. But you should be able to find your filesystem headers with dd and xxd (or any hexdump program). Where to look: - The first partition starts one track into the disk; typically that's 63 512-byte sectors. - The second, third, and fourth partitions are usually on cylinder boundaries, with a cylinder typically being 63 * 255 512-byte sectors. - If you had more than four partitions, then the last physical partition has a partition table at the beginning. The first logical partition will begin one track into that physical partition. What to look for: - For ext3 filesystems, a superblock begins 1024 bytes into the partition. At offset 0x38 in the superblock you should find the magic number 0x53ef (big-endian). - For swap partitions, look at the first 4096 bytes. At the end of that page you should find the string SWAPSPACE2. - For LVM physical volumes you should see an LVM label 512 bytes from the beginning of the partition. _______________________________________________ Linux-PowerEdge mailing list [email protected] https://lists.us.dell.com/mailman/listinfo/linux-poweredge Please read the FAQ at http://lists.us.dell.com/faq
