Feature #3344
closed
ceph-disk-prepare?: provide some sort of tool to clear out a disk, with prejudice
Added by Anonymous over 11 years ago.
Updated about 11 years ago.
Description
"sgdisk --zap-all --clear" just doesn't clear out all the possible funky states a disk may be in.
A simple "dd if=/dev/zero of=/dev/sdX" is enough, but writes the whole disk.
Trying to limit the dd with count of blocks only overwrites the first copy of the GPT data, just making the tools use the copy that is near the end of the disk.
Figure out how to wipe out a disk reliably.
Ideally, sgdisk would be made reliable. This might be good enough to be a useful workaround: in ceph-disk-prepare, just before calling sgdisk --zap, run:
import os
def zap_backup_gpt(dev, lba_size=4096):
"""
Wipe out the backup GPT on disk `dev`.
Overwrites last 33 LBAs of the disk with zero. Real world LBA is
normally 512 bytes, but to be safe we're going to default to 4k
sectors here, which means we typically overwrite more than
necessary, but still not too much for it to be slow.
Caution: This erases data!
"""
size = 33 * lba_size
with file(dev, 'wb') as f:
f.seek(-size, os.SEEK_END)
f.write(size*'\0')
- Translation missing: en.field_position set to 32
- Status changed from New to Resolved
added a whiel back, commit:b2ff6e8c9d96dee2c063b126de7030a5c2ae0d02
Also available in: Atom
PDF