1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
#!/usr/bin/perl -wT
# Check various system parameters for PostgreSQL. This needs to be run as root.
#
# (C) 2005-2009 Martin Pitt <mpitt@debian.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
use strict;
use PgCommon;
# Check write cache setting for given drive.
# Arguments: <device>
# Returns: 0 = disabled, 1 = enabled, -1: could not determine
sub get_device_write_cache {
open DRV, $_[0] or return -1;
sub HDIO_GET_WCACHE () {0x30e;}
my $pval = pack 'l', 0;
ioctl DRV, &HDIO_GET_WCACHE, $pval or return -1;
my ($val) = unpack 'l', $pval;
close DRV;
return $val;
}
error 'This command needs to be executed as root' if $> != 0;
# collect write cache-enabled drives with databases
my %drive_wcache;
my %seen;
for my $v (get_versions) {
for my $c (get_version_clusters $v) {
my $datadir = PgCommon::cluster_data_directory $v, $c;
my $drv = PgCommon::get_file_device $datadir;
$drv =~ s/[0-9]+$//;
unless (exists $seen{$drv}) {
$drive_wcache{$drv} = 1 if (get_device_write_cache $drv) > 0;
$seen{$drv} = 1;
}
}
}
my @unsave_drives = keys %drive_wcache;
if (@unsave_drives) {
print 'Warning: The following devices contain databases and have write
caching enabled: ', (join ' ', @unsave_drives), '
This could destroy the integrity of your databases in the event of power
failure. Consider disabling the write cache with "hdparm -W 0 <device>".
';
}
|
