On 22/10/12 10:07, sam tygier wrote: > hi, > > I have a 2 drive btrfs raid set up. It was created first with a single drive, and then adding a second and doing > btrfs fi balance start -dconvert=raid1 /data > > the original drive is showing smart errors so i want to replace it. i dont easily have space in my desktop for an extra disk, so i decided to proceed by shutting down. taking out the old failing drive and putting in the new drive. this is similar to the description at > https://btrfs.wiki.kernel.org/index.php/Using_Btrfs_with_Multiple_Devices#Replacing_Failed_Devices > (the other reason to try this is to simulate what would happen if a drive did completely fail). > > so after swapping the drives and rebooting, i try to mount as degraded. i instantly get a kernel panic, http://www.hep.man.ac.uk/u/sam/pub/IMG_5397_crop.png > > so far all this has been with 3.5 kernel. so i upgraded to 3.6.2 and tried to mount degraded again. > > first with just sudo mount /dev/sdd2 /mnt, then with sudo mount -o degraded /dev/sdd2 /mnt > > [ 582.535689] device label bdata devid 1 transid 25342 /dev/sdd2 > [ 582.536196] btrfs: disk space caching is enabled > [ 582.536602] btrfs: failed to read the system array on sdd2 > [ 582.536860] btrfs: open_ctree failed > [ 606.784176] device label bdata devid 1 transid 25342 /dev/sdd2 > [ 606.784647] btrfs: allowing degraded mounts > [ 606.784650] btrfs: disk space caching is enabled > [ 606.785131] btrfs: failed to read chunk root on sdd2 > [ 606.785331] btrfs warning page private not zero on page 3222292922368 > [ 606.785408] btrfs: open_ctree failed > [ 782.422959] device label bdata devid 1 transid 25342 /dev/sdd2 > > no panic is good progress, but something is still not right. > > my options would seem to be > 1) reconnect old drive (probably in a USB caddy), see if it mounts as if nothing ever happened. or possibly try and recover it back to a working raid1. then try again with adding the new drive first, then removing the old one. > 2) give up experimenting and create a new btrfs raid1, and restore from backup > > both leave me with a worry about what would happen if a disk in a raid 1 did die. (unless is was the panic that did some damage that borked the filesystem.) Some more details. If i reconnect the failing drive then I can mount the filesystem with no errors, a quick glance suggests that the data is all there. Label: 'bdata' uuid: 1f07081c-316b-48be-af73-49e6f76535cc Total devices 2 FS bytes used 2.50TB devid 2 size 2.73TB used 2.73TB path /dev/sde1 <-- this is the drive that i wish to remove devid 1 size 2.73TB used 2.73TB path /dev/sdd2 sudo btrfs filesystem df /mnt Data, RAID1: total=2.62TB, used=2.50TB System, DUP: total=40.00MB, used=396.00KB System: total=4.00MB, used=0.00 Metadata, DUP: total=112.00GB, used=3.84GB Metadata: total=8.00MB, used=0.00 is the failure to mount when i remove sde due to it being dup, rather than raid1? is adding a second drive to a btrfs filesystem and running btrfs fi balance start -dconvert=raid1 /mnt not sufficient to create an array that can survive the loss of a disk? do i need -mconvert as well? is there an -sconvert for system? thanks Sam -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
