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#!/usr/bin/ruby
#
# Program to free up space on the backup-storage volume, by removing
# backups (whether by age, or importance).
#
$LOAD_PATH.unshift('/usr/lib/byteback')
require 'trollop'
require 'byteback'
require 'sys/filesystem'
include Byteback
include Byteback::Log
include Byteback::Util
opts = Trollop.options do
banner "Prune old backup directories to ensure there's enough space"
opt :minpercent, 'Start prune when disk has less than this %age free',
type: :integer,
default: 5
opt :maxpercent, 'Stop prune when disk has more than this %age free',
type: :integer,
default: 10
opt :list, 'List backups in pruning order, no other action'
opt :prune, 'Prune the next backup if necessary'
opt :prune_force, 'Prune the next backup regardless'
opt :order, "Order backups by 'age' or 'importance'",
type: :string,
default: 'importance'
opt :verbose, 'Show debugging messages'
end
@order = opts[:order]
@verbose = opts[:verbose]
@do_list = opts[:list]
@do_prune = opts[:prune]
@do_prune_force = opts[:prune_force]
@minpercent = opts[:minpercent]
@maxpercent = opts[:maxpercent]
@do_prune = true if @do_prune_force
fatal('Must specify one of --prune or --list') unless
(@do_prune || @do_list) &&
!(@do_prune && @do_list)
fatal("Must specify --order as 'age' or 'importance'") unless
@order == 'age' || @order == 'importance'
if BackupDirectory.all.empty?
fatal('No backup directories found, need to run byteback-snapshot')
end
lock_out_other_processes('byteback-prune')
@df_history = DiskFreeHistory.new(ENV['HOME'])
begin
@df_history.new_reading!
rescue Errno::ENOSPC
if @do_list
warn("Couldn't write disk history file due to lack of space, ignoring")
else
warn("Couldn't write disk history file due to lack of space, going to --prune-force")
@do_prune = @do_prune_force = true
end
rescue => anything_else
error("Couldn't record disk history of #{@df_history.mountpoint} in #{@df_history.history_file}, installation problem?")
raise
end
gradient_30m = @df_history.gradient(1800)
# Check whether we should still be pruning
#
@free = @df_history.list.last.percent_free
PRUNING_FLAG = "#{ENV['HOME']}/.byteback.pruning"
if @do_prune_force
info('Forcing prune')
elsif @free <= @minpercent && !File.exist?(PRUNING_FLAG)
info("Starting prune #{@free}% -> #{@maxpercent} free")
File.write(PRUNING_FLAG, '')
elsif @free >= @maxpercent && File.exist?(PRUNING_FLAG)
info("Stopping prune, reached #{@free}% free")
File.unlink(PRUNING_FLAG)
elsif File.exist?(PRUNING_FLAG)
info("Continuing prune #{@free}% -> #{@maxpercent}, gradient = #{gradient_30m}")
end
debug("Disc free #{@free}%, 30m gradient = #{gradient_30m}")
def snapshots_in_order
list = BackupDirectory.all_snapshots
if @order == 'importance'
Snapshot.sort_by_importance(list)
elsif @order == 'age'
list.sort.reverse
else
fail ArgumentError.new("Unknown snapshot sort method #{method}")
end
end
snapshots = snapshots_in_order
if @do_list
print "Backups by #{@order}:\n"
snapshots.each_with_index do |snapshot, index|
print "#{sprintf('% 3d', index)}: #{snapshot.path}\n"
end
end
# Don't do anything if we've not got two hours of readings
#
unless @do_prune_force
if @df_history.list.last.time - @df_history.list.first.time < 1800
warn('Not enough disc space history to make a decision')
exit 0
end
end
exit 0 unless
(@do_prune && File.exist?(PRUNING_FLAG)) ||
@do_prune_force
exit 0 unless @do_prune_force || gradient_30m == 0
if snapshots.empty?
error('No snapshots to delete, is there enough disc space?')
exit 1
end
info("Deleting #{snapshots.last.path}")
log_system("/sbin/btrfs subvolume delete #{snapshots.last.path}")
|
