thin_metadata_size: new metadata size calculation tool

This commit is contained in:
Heinz Mauelshagen 2013-06-21 12:41:53 +02:00
parent f376fdfb49
commit 0b29c22ba9

View File

@ -0,0 +1,121 @@
#!/usr/bin/env ruby
#
# Copyright (C) 2013 Red Hat, GmbH
#
# This file is released under the GPL
#
#
# Script to calculate device-mapper thin privisioning
# metadata device size based on pool, block size and
# maximum expected thin provisioned devices.
#
require 'optparse'
require 'pathname'
#----------------------------------------------------------------
$prg = Pathname.new($0).basename
$btree_entrysize = 16
$btree_nodesize = 4096
def init_units
units = Hash.new
units[:chars] = "sKkMmGgTtPpEeZzYy"
units[:strings] = [ 'sectors',
'kilobytes', 'kibibytes', 'megabytes', 'mebibytes',
'gigabytes', 'gibibytes', 'terabytes', 'tebibytes',
'petabytes', 'pebibytes', 'exabytes', 'ebibytes',
'zetabytes', 'zebibytes', 'yottabytes', 'yobibytes' ]
units[:factors] = Array.new
units[:factors][0] = 512
1.step(8) do |e|
units[:factors][(e - 1) * 2 + 1] = 1024**e
units[:factors][(e - 1) * 2 + 2] = 1000**e
end
units
end
def check_opts(opts)
abort "#{$prg} - 3 arguments required!" if opts.length < 3
abort "#{$prg} - poolsize must be much larger than blocksize" if opts[:poolsize] < opts[:blocksize] * 16
abort "#{$prg} - maximum number of thin provisioned devices must be > 0" if opts[:maxthins].nil? || opts[:maxthins] == 0
end
def to_sectors(size, units)
unit_chars = units[:chars]
a = size.split(/[#{unit_chars}]/)
s = size.to_i.to_s
abort "#{$prg} - only one unit character allowed!" if a.length > 1 || size.length - s.length > 1
abort "#{$prg} - invalid unit specifier!" if s != a[0]
idx = unit_chars.index(size[a[0].length])
r = size.to_i * units[:factors][idx] / 512
r
end
def parse_command_line(argv, units)
opts = {}
unit_chars = units[:chars]
os = OptionParser.new do |o|
o.banner = "Thin Provisioning Metadata Size Calculator.\nUsage: #{$prg} [opts]"
o.on('-b', '--blocksize BLOCKSIZE', String,
"Block size, ie. allocation unit size for thin provisioned devices.") do |bs|
opts[:blocksize] = to_sectors(bs, units)
end
o.on('-s', '--poolsize SIZE', String, "Size of the pool device.") do |ps|
opts[:poolsize] = to_sectors(ps, units)
end
o.on('-m', '--maxthins MAXTHINS', Integer, "Size of the pool device.") do |mt|
opts[:maxthins] = mt
end
o.on('-u', '--units [skKmMgGtTpP]', String, "Output unit specifier.") do |u|
if u =~ /[#{unit_chars}]/
opts[:units] = u
else
abort "#{$prg} - output unit specifier invalid."
end
end
o.on('-n', '--numeric-only', "Output numeric value only.") do
opts[:numeric] = true || nil
end
o.on('-h', '--help', "Outout this help.") do
puts o
exit
end
end
begin
os.parse(argv)
rescue OptionParser::ParseError => e
abort "#{$prg} #{e}\n#{$prg} #{os}"
end
check_opts(opts)
opts
end
def entries_per_node
btree_node_headersize = 64
($btree_nodesize - btree_node_headersize) / $btree_entrysize
end
def estimated_result(opts, units)
idx = opts[:units] ? units[:chars].index(opts[:units]) : 0
r = 1.0 + ((opts[:poolsize] / opts[:blocksize] / entries_per_node) + opts[:maxthins]) * 512 / 8
r /= units[:factors][idx]
tmp = "%.2f" % r
# FIXME: avoid zero decimal places
r = tmp.to_f > 0.0 ? tmp : "%.4e" % r
r = "#{$prg} estimated metadata area size is #{r} #{units[:strings][idx]}." if !opts[:numeric]
r
end
#----------------------------------------------------------------
# Main
units = init_units
puts estimated_result(parse_command_line(ARGV, units), units)