On 14/05/15 14:54, d tbsky wrote: > Hi: > I think I did something wrong and cause mdadm data corruption. > but I am curious which steps brings me down. hope someone can told me > about it. > > I have two hosts forms a vm HA cluster. each one is a 2TB * 2 > mdadm raid 1. I need to test something but lack of disks, so I pull > one disk of each hosts. after testing, I put the disk back and let > mdadm rebuild. host B took several hours to rebuild and looks fine. > host A took only 5 min to rebuild. after completing rebuild, the > virtual machines stand above the raid crashed one by one. since I > know I have write many data bytes during the testing, host A should > not took only 5 min to recover. I must do something wrong to confuse > mdadm. below is what I done: > > 1. I test a 3 disk mdadm raid 5: sda (hostA sdb), sdb (hostB sdb), sdc > (new disk). I wrote about 5G data for system restore testing. > > 2. then I test a 4 disk mdadm raid10: sda (hostA sdb), sdb(hostB > sdb),sdc(new disk),sdd (new disk). I wrote about 5G data for system > restore testing. > > 3. then I test again a 4 disk mdadm rai10, but wrote about 120G data > for system restore testing. > > then I put back the disk to hostA and hostB (hot plugin, HOST A and B > are still running). at hostA I issue command blow: > mdadm --stop /dev/md126; mdadm --stop /dev/md127 (the plugged disk > has raid data on it and udev seems found it) > dd if=/dev/sda of=/dev/sdb bs=1k count=1000 (to recreate mbr > partition table). My guess is this is where you went wrong. Instead use a tool that will do this intelligently, quick google shows this: sgdisk -R=/dev/sdb /dev/sda sgdisk -G /dev/sdb Taken from: http://unix.stackexchange.com/questions/12986/how-to-copy-the-partition-layout-of-a-whole-disk-using-standard-tools My guess is you copied some data as well as the partition table, and that you are using a mdadm label which is stored at the beginning of the disk, and possibly are using bitmap on one server and not the other. Maybe if you could show some details from each of the raid arrays then more people can make more informed comments. My suggestion is to create *just* the partitions, and then add them to the array. Hope that helps. Regards, Adam -- Adam Goryachev Website Managers Ph: +61 2 8304 0000 adam@xxxxxxxxxxxxxxxxxxxxxx Fax: +61 2 8304 0001 www.websitemanagers.com.au -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
