autconf: support build of thin_metadata_size.c

thin-provisioning/thin_metadata_size.rb

@@ -0,0 +1,115 @@
+#!/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 and snapshots.
+#
+
+require 'optparse'
+require 'pathname'
+
+#----------------------------------------------------------------
+
+$prg = Pathname.new($0).basename
+
+def init_units
+  units = {}
+  units[:bytes_per_sector] = 512
+  units[:chars] = "bskKmMgGtTpPeEzZyY"
+  units[:strings] = [ 'bytes', 'sectors',
+                      'kilobytes', 'kibibytes', 'megabytes',  'mebibytes',
+                      'gigabytes', 'gibibytes', 'terabytes',  'tebibytes',
+                      'petabytes', 'pebibytes', 'exabytes',   'ebibytes',
+                      'zetabytes', 'zebibytes', 'yottabytes', 'yobibytes' ]
+  units[:factors] = [ 1, units[:bytes_per_sector] ]
+  1.step(8) { |e| units[:factors] += [ 1024**e, 1000**e ] }
+  units
+end
+
+def get_index(unit_char, units)
+  unit_char ? units[:chars].index(unit_char) : 1
+end
+
+def check_opts(opts)
+  abort "#{$prg} - 3 arguments required!" if opts.length < 3
+  abort "#{$prg} - block size must be > 0" if opts[:blocksize] <= 0
+  abort "#{$prg} - poolsize must be much larger than blocksize" if opts[:poolsize] < opts[:blocksize]
+  abort "#{$prg} - maximum number of thin provisioned devices must be > 0" if opts[:maxthins].nil? || opts[:maxthins] == 0
+end
+
+def to_bytes(size, units)
+  a = size.split(/[#{units[:chars]}]/)
+  s = size.to_i.to_s
+  abort "#{$prg} - only one unit character allowed!" if a.length > 1 || size.length - s.length > 1
+  abort "#{$prg} - invalid unit specifier!" if s != a[0]
+  size.to_i * units[:factors][get_index(size[a[0].length], units)]
+end
+
+def parse_command_line(argv, units)
+  opts = {}
+
+  os = OptionParser.new do |o|
+    o.banner = "Thin Provisioning Metadata Device Size Calculator.\nUsage: #{$prg} [opts]"
+    o.on("-b", "--block-size BLOCKSIZE[#{units[:chars]}]", String,
+         "Block size of thin provisioned devices.") do |bs|
+      opts[:blocksize] = to_bytes(bs, units)
+    end
+    o.on("-s", "--pool-size SIZE[#{units[:chars]}]", String, "Size of pool device.") do |ps|
+      opts[:poolsize] = to_bytes(ps, units)
+    end
+    o.on("-m", "--max-thins #MAXTHINS", Integer, "Maximum sum of all thin devices and snapshots.") do |mt|
+      opts[:maxthins] = mt
+    end
+    o.on("-u", "--unit [#{units[:chars]}]", String, "Output unit specifier.") do |u|
+      abort "#{$prg} - output unit specifier invalid." if u.length > 1 || !(u =~ /[#{units[:chars]}]/)
+      opts[:units] = u
+    end
+    o.on("-n", "--numeric-only", "Output numeric value only.") do
+      opts[:numeric] = true
+    end
+    o.on("-h", "--help", "Output this help.") do
+      puts o
+      exit
+    end
+  end
+
+  begin
+    os.parse!(argv)
+  rescue OptionParser::ParseError => e
+    abort "#{$prg} #{e}\n#{$prg} #{os}"
+  end
+
+  check_opts(opts)
+  opts
+end
+
+def mappings_per_block
+  btree_nodesize, btree_node_headersize, btree_entrysize = 4096, 64, 16
+  (btree_nodesize - btree_node_headersize) / btree_entrysize
+end
+
+def estimated_result(opts, units)
+  idx = get_index(opts[:units], units)
+  # double-fold # of nodes, because they aren't fully populated in average
+  r = (1.0 + (2 * opts[:poolsize] / opts[:blocksize] / mappings_per_block + opts[:maxthins])) * 8 * units[:bytes_per_sector] # in bytes!
+  r /= units[:factors][idx] # in requested unit
+  tmp = "%.2f" % r
+  if tmp.to_f > 0.0
+    r = tmp.to_i.to_f == tmp.to_f ? tmp.to_i : tmp
+  else
+    r = "%.2e" % r
+  end
+  r = "#{$prg} - estimated metadata area size is #{r} #{units[:strings][idx]}." if !opts[:numeric]
+  r
+end
+
+
+#----------------------------------------------------------------
+# Main
+#
+puts estimated_result(parse_command_line(ARGV, (units = init_units)), units)