find_block.pl是Oracle ASM项目开发组成员(http://asmsupportguy.blogspot.com)用perl写的脚本，脚本很实用，可以帮我们找到数据块在磁盘中对应的位置，她适应于ASMLIB，AFD(ASM Filter Driver) Disk，当然也适用于Exadata。这个脚本需要在GI环境下运行，要设置LD_LIBRARY_PATH，否则可能出现以下的错误。
[oracle@ohs1 ~]$ $ORACLE_HOME/perl/bin/perl find_block.pl +DATA_PGOLD/racdb/system01.dbf 128
Can't load '/oracle/product/112/perl/lib/site_perl/5.10.0/i686-linux-thread-multi/auto/DBD/Oracle/Oracle.so' for module DBD::Oracle: libclntsh.so.11.1: cannot open shared object file: No such file or directory at /oracle/product/112/perl/lib/5.10.0/i686-linux-thread-multi/DynaLoader.pm line 203. at find_block.pl line 35 Compilation failed in require at find_block.pl line 35. BEGIN failed--compilation aborted at find_block.pl line 35. [oracle@ohs1 ~]$
使用find_block.pl
$ echo $LD_LIBRARY_PATH[oracle@ohs1 ~]$ export LD_LIBRARY_PATH=$ORACLE_HOME/lib
[oracle@ohs1 ~]$ $ORACLE_HOME/perl/bin/perl find_block.pl +DATA_PGOLD/racdb/system01.dbf 1 dd if=/dev/oracleasm/disks/ASMDISK7 bs=8192 count=1 skip=2689 of=block_1.dd [oracle@ohs1 ~]$ $ORACLE_HOME/perl/bin/perl find_block.pl +DATA_PGOLD/racdb/system01.dbf 128 dd if=/dev/oracleasm/disks/ASMDISK8 bs=8192 count=1 skip=2944 of=block_128.dd [oracle@ohs1 ~]$ $ORACLE_HOME/perl/bin/perl find_block.pl +DATA_PGOLD/racdb/system01.dbf 256 dd if=/dev/oracleasm/disks/ASMDISK6 bs=8192 count=1 skip=2944 of=block_256.dd [oracle@ohs1 ~]$
find_block.pl脚本
#!$ORACLE_HOME/perl/bin/perl -w
#
# The find_block.pl constructs the command(s) to extract a block from ASM.
# For a complete info about this script see ASM Support Guy blog post:
# http://asmsupportguy.blogspot.com/2014/10/find-block-in-asm.html
#
# Copyright (C) 2014 Bane Radulovic
#
# 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 3 of the License, or 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
# at http://www.gnu.org/licenses/.
#
# Version 1.00, Oct 2014
# The initial release.
#
# Version 1.01, Oct 2014
# Minor improvements.
#
# Version 1.02, Oct 2014
# Added support for AFD disks.
#
# Version 1.03, Nov 2014
# Added sanity checks, e.g. if the requested block is reasonable,
# if the specified filename is valid, etc.
#
# Version 1.04, Nov 2014
# Improved the check for Exadata storage cell based disk.
#
use strict;
use DBI;
use DBD::Oracle qw(:ora_session_modes);
use POSIX;
# Handle the version query
die "find_block.pl version 1.04\n"
if ( $ARGV[0] =~ /^-v/i );
# Check the number of input arguments
die "Usage: \$ORACLE_HOME/perl/bin/perl find_block.pl filename block\n"
unless ( @ARGV == 2 );
# Get the filename from the first input argument
my $filename = shift @ARGV;
# Check if the filename makes sense.
# The 'minimum' filename is +DGNAME/filename,
# i.e. it has to begin with the '+' followed by a disk group name,
# followed by at least one '/', followed by directory or file name...
die "Error: The $filename is not a valid file name.\n"
unless ( $filename =~ /^\+\w/ && $filename =~ /\/\w/ );
# Get the disk group name out of the user specified filename
my $diskgroup_name = substr($filename, 1, index($filename, "/") -1 );
# Get the ASM file name out of the user specified filename
my $asmfile = substr($filename, rindex($filename, "/") +1 );
# Get the block number from the second input argument
my $block_number = shift @ARGV;
# Check if the block number is an integer
die "Usage: \$ORACLE_HOME/perl/bin/perl find_block.pl filename block\n"
unless ( $block_number =~ /^\d+$/ );
# Check if the ASM SID is set
die "Error: ASM SID not set.\n"
unless ( $ENV{ORACLE_SID} =~ /\+ASM/ );
# Connect to the (local) ASM instance
my $dbh = DBI->connect('dbi:Oracle:', "", "", { ora_session_mode => ORA_SYSDBA })
or die "$DBI::errstr\n";
# Check if the disk group exists and if it is mounted
my $group_number = &asm_diskgroup("group_number", $diskgroup_name);
die "Error: Disk group $diskgroup_name not mounted or does not exist.\n"
unless ( $group_number );
# Check if the user specified file exists in the disk group
my $file_number = &asm_alias("file_number", $asmfile, $group_number);
die "Error: File $asmfile does not exist in disk group $diskgroup_name.\n"
unless ( $file_number );
# Get the block size for the file
my $block_size = &asm_file("block_size", $group_number, $file_number);
# Get the number of blocks in the file
my $file_blocks = &asm_file("blocks", $group_number, $file_number);
# Check if the user specified block number makes sense
die "Error: Block range for file $asmfile is: 0 - $file_blocks.\n"
unless ( $block_number >= 0 && $block_number <= $file_blocks );
# Get the disk group AU size
my $au_size = &asm_diskgroup("allocation_unit_size", $diskgroup_name);
# Work out the blocks per AU and the virtual extent number
my $blocks_per_au = $au_size/$block_size;
my $xnum_kffxp = floor($block_number/$blocks_per_au);
# Get the disk and AU numbers into the @disk_au array
my @disk_au = &asm_kffxp($file_number, $group_number, $xnum_kffxp);
die "Could not get any disk and AU numbers for file $asmfile.\n"
unless ( @disk_au );
# Get the disk path(s) and generate the block extract command(s)
while ( @disk_au ) {
# Do not assume anything
my $storage_cell = "FALSE";
# Get the disk number from @disk_au
my $disk_number = shift @disk_au;
# Get the AU number from @disk_au
my $au_number = shift @disk_au;
# Get the path for that disk number
my $path = &asm_disk("path", $group_number, $disk_number);
# If there is no path move to the next disk
if ( ! $path ) {
next;
}
# If ASMLIB is in use, the path will return ORCL:DISKNAME.
# Set the path to /dev/oracleasm/disks/DISKNAME
elsif ( $path =~ /ORCL:(.*)/ ) {
$path = "/dev/oracleasm/disks/".$1;
}
# If ASM Filter Driver (AFD) is in use, the path will return AFD:DISKNAME.
# Get the actual path from /dev/oracleafd/disks/DISKNAME
elsif ( $path =~ /AFD:(.*)/ ) {
if ( ! open AFDDISK, "/dev/oracleafd/disks/".$1 ) { next }
else { chomp($path = <AFDDISK>) }
}
# For Exadata storage cell based disk, the path will start with o/IP address
elsif ( $path =~ /^o\/\d{1,3}\./ ) {
$storage_cell = "TRUE";
}
if ( $storage_cell eq "TRUE" ) {
# Construct the kfed command for Exadata storage cell based disk
# dev=$path ausz=$au_size aunum=$au_number blksz=$block_size blknum=$block_number
# The grep filters out the kfed stuff
print "kfed read dev=$path ausz=$au_size aunum=$au_number blksz=$block_size blknum=$block_number | grep -iv ^kf > block_$block_number.txt\n";
}
else {
# Construct the dd command
# if=$path bs=$block_size count=1 skip=$skip of=block_$block_number.dd
my $skip=$au_number*$blocks_per_au + $block_number%$blocks_per_au;
print "dd if=$path bs=$block_size count=1 skip=$skip of=block_$block_number.dd\n";
}
}
# We are done. Disconnect from the (local) ASM instance
$dbh->disconnect;
# Subs
# Get a column from v$asm_file for a given group number and file number
sub asm_file {
my $col = shift @_;
my $group_number = shift @_;
my $file_number = shift @_;
my $sql = $dbh->prepare("select $col from v\$asm_file where group_number=$group_number and file_number=$file_number");
$sql->execute;
my $col_value = $sql->fetchrow_array;
$sql->finish;
return $col_value;
}
# Get a column from v$asm_alias for a given (file) name and group number
sub asm_alias {
my $col = shift @_;
my $name = shift @_;
my $group_number = shift @_;
my $sql = $dbh->prepare("select $col from v\$asm_alias where lower(name)=lower('$name') and group_number=$group_number");
$sql->execute;
my $col_value = $sql->fetchrow_array;
$sql->finish;
return $col_value;
}
# Get a column from v$asm_diskgroup for a given disk group name
sub asm_diskgroup {
my $col = shift @_;
my $name = shift @_;
my $sql = $dbh->prepare("select $col from v\$asm_diskgroup where name=upper('$name')");
$sql->execute;
my $col_value = $sql->fetchrow_array;
$sql->finish;
return $col_value;
}
# Get a column from v$asm_disk for a given group number and disk number
sub asm_disk {
my $col = shift @_;
my $group_number = shift @_;
my $disk_number = shift @_;
my $sql = $dbh->prepare("select $col from v\$asm_disk where group_number=$group_number and disk_number=$disk_number");
$sql->execute;
my $col_value = $sql->fetchrow_array;
$sql->finish;
return $col_value;
}
# Get the disk and AU numbers from x$kffxp for a given virtual extent number.
# This will return one row for an external redundancy file,
# two rows for a normal redundancy and three rows for a high redundancy.
# Well, it will return an array with disk and AU pairs, not rows.
sub asm_kffxp {
my $file_number = shift @_;
my $group_number = shift @_;
my $xnum = shift @_;
# The @disk_au array to hold the disk number, AU number rows
my @disk_au;
my $sql = $dbh->prepare("select disk_kffxp, au_kffxp from x\$kffxp where number_kffxp=$file_number and group_kffxp=$group_number and xnum_kffxp=$xnum");
$sql->execute;
# Expecting one disk number and one AU number per row
while ( my @row = $sql->fetchrow_array) {
# Add each (element of the) row to @disk_au array
foreach ( @row ) { push @disk_au, $_ }
}
$sql->finish;
return @disk_au;
}
