I am willing to bet you know that the SAN has shifted the beginning of the physical disk off by a few bytes. I've seen this before. Its a bitch to get your files off of a disk that has done this but it is possible.
If you run 'fdisk -l' do you get messages about the starting cylinders on the device not marrying up? Its usually in brackets around each partition declaration.
Do you manage to find the LVM groups but not the disk itself? Is the LVM device made up of multiple SAN disks and just one is affected?
The following script is going to try to search for the correct offset on /dev/sdb where your lvm partition starts. No guarantees it will find anything. If it does, you might be in a good position to recover your data.
#!/usr/bin/python
import sys
def BoyerMooreHorspool(pattern, text):
m = len(pattern)
n = len(text)
if m > n: return -1
skip = []
for k in range(256): skip.append(m)
for k in range(m - 1): skip[ord(pattern[k])] = m - k - 1
skip = tuple(skip)
k = m - 1
while k < n:
j = m - 1; i = k
while j >= 0 and text[i] == pattern[j]:
j -= 1; i -= 1
if j == -1: return i + 1
k += skip[ord(text[k])]
return -1
if __name__ == '__main__':
giveup = 1024*1024*1024*2
lba_offset = 0
text = ""
disk = open('/dev/sdb', 'r')
while disk.tell() < giveup:
#print "Checking: %f" % (lba_offset/(1024*1024))
text = disk.read(1048576)
s = BoyerMooreHorspool("\x00\x00\x00LVM2", text)
if s > -1:
print "Try offset: %d" % ((lba_offset+int(s))-533)
sys.exit(0)
else:
lba_offset += 1048576
print "Unable to find LVM position!"
Can you return what output you get?
