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* Prototype store optimiser. It searched the Nix store for identical

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files and hard-links them to each other to save disk space.

  Currently it doesn't actually do the hard-linking, it just reports
  the amount of space saved if it did.
This commit is contained in:
Eelco Dolstra 2005-01-05 09:58:12 +00:00
parent a03397be4c
commit 6af4a5a71f
1 changed files with 69 additions and 0 deletions
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scripts/optimise-store.pl Executable file
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#! /usr/bin/perl -w
use strict;
{ my $ofh = select STDOUT;
$| = 1;
select $ofh;
}
#my @paths = ("/nix/store/caef3a49150506d233f474322a824e50-glibc-2.3.3", "/nix/store/a8a9d585d1ad4b1bc911be7743b3b996-glibc-2.3.3");
my @paths = ("/nix/store");
my $tmpfile = "/tmp/nix-optimise-hash-list";
#my $tmpfile = "/data/nix-optimise-hash-list";
system("find @paths -type f -print0 | xargs -0 md5sum -- > $tmpfile") == 0
or die "cannot hash store files";
system("sort $tmpfile > $tmpfile.sorted") == 0
or die "cannot sort list";
open LIST, "<$tmpfile.sorted" or die;
my $prevFile;
my $prevHash;
my $totalSpace = 0;
my $savedSpace = 0;
my $files = 0;
while (<LIST>) {
# print "D";
/^([0-9a-f]*)\s+(.*)$/ or die;
my $curFile = $2;
my $curHash = $1;
# print "A";
my $fileSize = (stat $curFile)[7];
# print "B";
# my $fileSize = 1;
$totalSpace += $fileSize;
if (defined $prevHash && $curHash eq $prevHash) {
# print "$curFile = $prevFile\n";
$savedSpace += $fileSize;
} else {
$prevFile = $curFile;
$prevHash = $curHash;
}
print "." if ($files++ % 100 == 0);
#print ".";
# print "C";
}
print "\n";
print "total space = $totalSpace\n";
print "saved space = $savedSpace\n";
my $savings = ($savedSpace / $totalSpace) * 100.0;
print "savings = $savings %\n";
close LIST;