ides-mdstat

#! /usr/bin/env python
#
"""
Report on the disk device to MD array mapping.

Compares the actual state (as read from ``/proc/mdstat``)
with the intended configuration (as read from
``/usr/local/etc/mdadm.conf.ESPFS``).
"""

import re
import sys


# read intended array devices from /usr/local/etc/mdadm.conf.ESPFS
intended = { }
fd = open('/usr/local/etc/mdadm.conf.ESPFS')
NODEV = len('/dev/')
for line in fd:
    line = line.strip()
    if line.startswith('DEVICE'):
        devs = line.split()[1:]
    elif line.startswith('ARRAY'):
        md = line.split()[1][NODEV:]
        intended[md] = frozenset([ devname[NODEV:] for devname in devs])

# read actual array devices from /proc/mdstat
actual = { }
CLEAN_MD_LINE = re.compile(r'\[[0-9]+\]')
fd = open('/proc/mdstat')
for line in fd:
    line = line.strip()
    if line.startswith('md'):
        # md12 : active raid6 sdc[0] sdar[9] sdaj[8] sdt[7] sdl[6] sdd[5] sdaq[4] sdai[3] sdaa[2] sdk[1]
        line = CLEAN_MD_LINE.sub('', line)
        parts = line.split()
        md = parts[0]
        actual[md] = frozenset(parts[4:])

# compare
def names(seq):
    return str.join(' ', seq)

failed = 0
for md in sorted(intended.keys()):
    if md not in actual:
        print("%s: NOT STARTED" % md)
        failed += 1
    elif actual[md] == intended[md]:
        print ("%s: ok" % md)
    else:
        not_actual = intended[md] - actual[md]
        not_intended = actual[md] - intended[md]
        if len(not_intended) == 0:
            print ("%s: MISSING DEVICE(S): %s" % (md, names(not_actual)))
        elif len(not_actual) == 0:
            print ("%s: UNEXPECTED DEVICE(S): %s" % (md, names(not_intended)))
        elif len(actual[md]) == len(intended[md]):
            print ("%s: SHOULD HAVE %s, HAS %s INSTEAD"
                   % (md, names(not_actual), names(not_intended)))
        failed +=1

for md in sorted(actual.keys()):
    if md not in intended:
        print("%s: UNEXPECTED MD ARRAY!" % md)
        failed += 1

sys.exit(failed)