[ale] ISCSI

[Brian Pitts]

On 09/25/2009 05:25 PM, Brandon Colbert wrote:

> 
> My other question is how do I completely wipe all LVM configuration?
> 

Take a look at

https://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5.4/html/Logical_Volume_Manager_Administration/LVM_components.html

"The underlying physical storage unit of an LVM logical volume is a
block device such as a partition or whole disk. To use the device for an
LVM logical volume the device must be initialized as a physical volume
(PV). Initializing a block device as a physical volume places a label
near the start of the device.

By default, the LVM label is placed in the second 512-byte sector. You
can overwrite this default by placing the label on any of the first 4
sectors. This allows LVM volumes to co-exist with other users of these
sectors, if necessary.

An LVM label provides correct identification and device ordering for a
physical device, since devices can come up in any order when the system
is booted. An LVM label remains persistent across reboots and throughout
a cluster.

The LVM label identifies the device as an LVM physical volume. It
contains a random unique identifier (the UUID) for the physical volume.
It also stores the size of the block device in bytes, and it records
where the LVM metadata will be stored on the device.

The LVM metadata contains the configuration details of the LVM volume
groups on your system. By default, an identical copy of the metadata is
maintained in every metadata area in every physical volume within the
volume group. LVM metadata is small and stored as ASCII.

Currently LVM allows you to store 0, 1 or 2 identical copies of its
metadata on each physical volume. The default is 1 copy. Once you
configure the number of metadata copies on the physical volume, you
cannot change that number at a later time. The first copy is stored at
the start of the device, shortly after the label. If there is a second
copy, it is placed at the end of the device. If you accidentally
overwrite the area at the beginning of your disk by writing to a
different disk than you intend, a second copy of the metadata at the end
of the device will allow you to recover the metadata."

-- 
All the best,
Brian Pitts