On Wed, 2006-10-04 at 15:10 -0400, John Ward wrote: > Question regarding disk changes for LVMs. Are there any known scenarios > where the on disk information will change (automatically) after the > device(s) are detected and probed by the system? > > My scenario is, I want to plug my LVM drive(s) into a different machine > (via external USB) for analysis. I want the drives to remain 100% > unmodified. > > I would like to setup my configuration such that no disk changes will > occur. Does anything within the LVM or DM realm modify the on-disk > metadata under normal circumstances, or if a corrupted/broken LVM scheme > is detected (partial or bad disk, etc.)? > > In an attempt to gain absolute control over the detection and mounting > process, I've set the global configuration file to test mode: > > /etc/lvm/lvm.conf: > ... > global { > ... > test = 1 > ... > > > After that, once I plug my device in, I set the LVM_SYSTEM_DIR env > variable to point to my own configuration (because I don't want to > twiddle with the system-wide one anymore than I have to). > > I then use "vgchange --partial -a y" to access the new device, and > create the /dev nodes. > > In my custom lvm.conf (located in the $LVM_SYSTEM_DIR) I've set a few > paranoid settings, including: > > filter = ... (only accept /dev/sd* devices) > write_cache_state = 0 > backup = 0 > archive = 0 > locking_type = 0 > > Setting test mode in this configuration wasn't allowing me to do the > vgchange, so I left that off. > > Hope this isn't too open ended of a question, short if diving into the > source code, I've tried to research to what extent LVM might > automatically twiddle bits on the drive. > > Thanks in advance. Try to use hdparm to set your hard-drive in read-only mode.
Attachment:
signature.asc
Description: This is a digitally signed message part
_______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/