Source Code for Module ganeti.utils.lvm

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 2  # 
 3   
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20   
21  """Utility functions for LVM. 
22   
23  """ 
24   
25  from ganeti import constants 
26   
27   
28 -def CheckVolumeGroupSize(vglist, vgname, minsize): 
29    """Checks if the volume group list is valid. 
30   
31    The function will check if a given volume group is in the list of 
32    volume groups and has a minimum size. 
33   
34    @type vglist: dict 
35    @param vglist: dictionary of volume group names and their size 
36    @type vgname: str 
37    @param vgname: the volume group we should check 
38    @type minsize: int 
39    @param minsize: the minimum size we accept 
40    @rtype: None or str 
41    @return: None for success, otherwise the error message 
42   
43    """ 
44    vgsize = vglist.get(vgname, None) 
45    if vgsize is None: 
46      return "volume group '%s' missing" % vgname 
47    elif vgsize < minsize: 
48      return ("volume group '%s' too small (%s MiB required, %d MiB found)" % 
49              (vgname, minsize, vgsize)) 
50    return None 
51   
52   
53 -def LvmExclusiveCheckNodePvs(pvs_info): 
54    """Check consistency of PV sizes in a node for exclusive storage. 
55   
56    @type pvs_info: list 
57    @param pvs_info: list of L{LvmPvInfo} objects 
58    @rtype: tuple 
59    @return: A pair composed of: 1. a list of error strings describing the 
60      violations found, or an empty list if everything is ok; 2. a pair 
61      containing the sizes of the smallest and biggest PVs, in MiB. 
62   
63    """ 
64    errmsgs = [] 
65    sizes = [pv.size for pv in pvs_info] 
66    # The sizes of PVs must be the same (tolerance is constants.PART_MARGIN) 
67    small = min(sizes) 
68    big = max(sizes) 
69    if LvmExclusiveTestBadPvSizes(small, big): 
70      m = ("Sizes of PVs are too different: min=%d max=%d" % (small, big)) 
71      errmsgs.append(m) 
72    return (errmsgs, (small, big)) 
73   
74   
75 -def LvmExclusiveTestBadPvSizes(small, big): 
76    """Test if the given PV sizes are permitted with exclusive storage. 
77   
78    @param small: size of the smallest PV 
79    @param big: size of the biggest PV 
80    @return: True when the given sizes are bad, False otherwise 
81    """ 
82    # Test whether no X exists such that: 
83    #   small >= X * (1 - constants.PART_MARGIN)  and 
84    #   big <= X * (1 + constants.PART_MARGIN) 
85    return (small * (1 + constants.PART_MARGIN) < 
86            big * (1 - constants.PART_MARGIN)) 
87