> Hi, > > On Tue, Sep 14, 2010 at 06:55:36PM +0200, Ma Begaj wrote: >> Hi, >> >> >> I got a new HDD a few days ago and I put it in an external case and connected >> it over USB with my home server. It is a 2000GB WD disk, WD20EARS. > > That would be one of the 2kB sector drives... you mean 4kb? > >> I already read a few articles how should I format this "special" >> drive, and I did it like this: >> http://ubuntuforums.org/showthread.php?t=1456251 >> >> I set the partition to begin on sector 64 (instead of 63), run >> luksFormat, run luksOpen, >> created XFS and copied my files on this disk. I umounted it later and >> I rebooted >> the server today. >> >> First thing I noticed is that disk/paritions are not visible in >> /dev/disk/by-uuid/ although >> /dev/sdm and /dev/sdm1 are available. fdisk also does not look same >> as before: > > Not good. > >> fdisk output: >> -------------- >> root@road:/dev/disk/by-uuid# fdisk /dev/sdm >> >> The number of cylinders for this disk is set to 243201. >> There is nothing wrong with that, but this is larger than 1024, >> and could in certain setups cause problems with: >> 1) software that runs at boot time (e.g., old versions of LILO) >> 2) booting and partitioning software from other OSs >> (e.g., DOS FDISK, OS/2 FDISK) >> >> Command (m for help): p >> >> Disk /dev/sdm: 2000.3 GB, 2000398934016 bytes >> 255 heads, 63 sectors/track, 243201 cylinders >> Units = cylinders of 16065 * 512 = 8225280 bytes >> Disk identifier: 0x00000000 >> >> Device Boot Start End Blocks Id System >> /dev/sdm1 1 243202 1953514552 83 Linux > > You did create one large partition? yes just one filling whole disk. > > What is the output of "fdisk -lu /dev/sdm1"? > root@road:/dev/disk/by-uuid# fdisk -lu /dev/sdm1 Disk /dev/sdm: 2000.3 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units = sectors of 1 * 512 = 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdm1 64 3907029167 1953514552 83 Linux Well, it looks good. > >> -------------- >> >> "Start" is 1 instead of 64.... pretty strange because I set it to 64 >> when I was making this partition. > > You set it to 64 sectors. The 1 is a cylinder. You cannto see in this > view where exactly the partition starts. Use the -u option to fdisk. Good to know. Thanks. > >> >> luksOpen does not work and luksDump/isLuks reported that /dev/sdm1 is >> not luks partition. > > Interesting. > >> I have cryptsetup 1.0.5 on my server. > > Aehm, that is hiostoric. Please try with the current one, > which would be 1.1.3. Right now before continuing with the rest? I have 3 other luks partitions on this machine. Should I expect some hiccups? I am planning to upgrade whole system in the next week and if possible I will wait until than. > >> There are two questions for me here: >> 1. I have luksDump of /dev/sdm1 before this happened. Can I use >> luksDump ouput to >> recover/overwrite Luks partition? > > I think not, but I am not sure. Before trying that, lets figure > out whether this is simply an offset issue. Can you look > through the start of the disk and give the offset where the > "LUKS" string is exactly? > > Something like this should do the trick: > > hd /dev/sdm | grep LUKS "hd"? I don't have hd command on my server. but I found the position with with dd and vi: dd if=/dev/sdm of=/tmp/sdm bs=32256 count=1 obs=10240 skip=1 this gives me LUKS on the beginning of /tmp/sdm so offset should be 32256: LUKSº¾^@^Aaes^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@cbc-essiv:sha256^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@sha1^@^@^@^@^@^@^@^@^@^ @^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^D^H^@^@^@^Pq^W:<93>CEÚñè©äkÛ)ÍQlÉ<8f>¦ç0à<9b>m^Yr ¡^E and like this: root@road:/dev/disk/by-uuid# dd if=/dev/sdm of=/tmp/sdm bs=1024000 count=1 1+0 records in 1+0 records out 1024000 bytes (1.0 MB) copied, 0.0327064 s, 31.3 MB/s root@road:/dev/disk/by-uuid# grep -ob --binary-files=text LUKS /tmp/sdm 32256:LUKS or grep directly on /dev/sdm [ 32256 ] should be offset. What should I do with this? > >> fdisk reports "start" on sector 1 instead of 64, which means that >> something there went wrong. > > No, see above. > >> Or not? Ideas? If I can use luksDump to recover luks-header should the >> partition table maybe be >> rewritten beginning with sector 64 before I recreate luks header. >> >> >> 2. How all this could happen? >> >> I would be very happy to experiment with this, to repeat all the steps >> to recreat the situation >> if I know that I am able to recover my partition. Any ideas before I >> start to play with this? >> How much of the partition header should I backup before starting with >> all of this? > > See the FAQ. If you back up the first 100MB, you are on the safe side. > root@road:/dev/disk/by-uuid# dd if=/dev/sdm of=/root/sdm.iso bs=1024000 count=100 100+0 records in 100+0 records out 102400000 bytes (102 MB) copied, 3.01704 s, 33.9 MB/s >> >> p.s. I have all the data but I would like to avoid copying again >> because I have to copy everything >> (over 500gb) over SSH trough a 10mb connection > > Half a pound (500g) of 'b' though a 10 milli-bit connection? > Sounds like a pain (yes, capitalization can carry meaning). ;-). believe me even 10[M]b is pretty slow if you have to copy 500[GB]. Thanks M. _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
