dd操作数据文件

Posted on 2012 年 01 月 13 日 by 惜分飞

1.dd主要参数

       Copy a file, converting and formatting according to the operands.

       bs=BYTES
              force ibs=BYTES and obs=BYTES

       cbs=BYTES
              convert BYTES bytes at a time

       count=BLOCKS
              copy only BLOCKS input blocks

       ibs=BYTES
              read BYTES bytes at a time

       if=FILE
              read from FILE instead of stdin

       obs=BYTES
              write BYTES bytes at a time

       of=FILE
              write to FILE instead of stdout

       seek=BLOCKS
              skip BLOCKS obs-sized blocks at start of output

       skip=BLOCKS
              skip BLOCKS ibs-sized blocks at start of input

2.拷贝数据文件头部

[oracle@node1 chf]$ dd if=system01.dbf of=/tmp/dd_xifenfei01.dbf bs=8192 count=1
1+0 records in
1+0 records out
8192 bytes (8.2 kB) copied, 6.2e-05 seconds, 132 MB/s
[oracle@node1 chf]$ ll /tmp/dd_xifenfei01.dbf
-rw-r--r-- 1 oracle oinstall 8192 01-13 16:49 /tmp/dd_xifenfei01.dbf


BBED> set filename '/tmp/dd_xifenfei01.dbf'
        FILENAME        /tmp/dd_xifenfei01.dbf

BBED> set block 1
        BLOCK#          1

BBED> dump
 File: ././dd_xifenfei01.dbf (0)
 Block: 1                Offsets:    0 to  511           Dba:0x00000000
------------------------------------------------------------------------
 00a20000 0000c0ff 00000000 00000000 64590000 00200000 00a30200 7d7c7b7a 
 a0810000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 

 <32 bytes per line>

BBED> set block 2
BBED-00309: out of range block number (2)


BBED> set offset 8190
        OFFSET          8190

BBED> dump
 File: ././dd_xifenfei01.dbf (0)
 Block: 1                Offsets: 8190 to 8191           Dba:0x00000000
------------------------------------------------------------------------
 0000 

 <32 bytes per line>
--证明只有1个数据块(8192),并且拷贝数据文件头部成功

3.模拟创建文件

[oracle@node1 tmp]$ ll /tmp/dd_xifenfei02.dbf -h
-rw-r--r-- 1 oracle oinstall 1.0G 01-13 16:58 /tmp/dd_xifenfei02.dbf

4.拷贝数据块到一个文件中

[oracle@node1 chf]$ dd if=/tmp/dd_xifenfei01.dbf of=/tmp/dd_xifenfei02.dbf bs=8192 count=1
1+0 records in
1+0 records out
8192 bytes (8.2 kB) copied, 6e-05 seconds, 137 MB/s
[oracle@node1 chf]$ bbed
Password: 

BBED: Release 2.0.0.0.0 - Limited Production on Fri Jan 13 17:01:02 2012

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

************* !!! For Oracle Internal Use only !!! ***************

BBED> set filename '/tmp/dd_xifenfei02.dbf'

BBED> set block 1
        BLOCK#          1

BBED> dump
 File: ././dd_xifenfei02.dbf (0)
 Block: 1                Offsets:    0 to  511           Dba:0x00000000
------------------------------------------------------------------------
 00a20000 0000c0ff 00000000 00000000 64590000 00200000 00a30200 7d7c7b7a 
 a0810000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 

 <32 bytes per line>


BBED> set block 2
BBED-00309: out of range block number (2)


BBED> set offset 8190
        OFFSET          8190

BBED> dump
 File: ././dd_xifenfei02.dbf (0)
 Block: 1                Offsets: 8190 to 8191           Dba:0x00000000
------------------------------------------------------------------------
 0000 

 <32 bytes per line>

通过对比在2步骤中拷贝出来的数据文件头部，证明现在已经把该头部拷贝到了3步骤创建的新文件中

恢复被rm意外删除数据文件

Posted on 2011 年 12 月 31 日 by 惜分飞

一.模拟数据文件删除

[oracle@node1 ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.3.0 Production on Sat Dec 31 22:00:52 2011

Copyright (c) 1982, 2011, Oracle.  All rights reserved.

--数据库版本
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options

--所有数据文件
SQL> select name from v$datafile;

NAME
--------------------------------------------------------------------------------
/opt/oracle/oradata/ora11g/system01.dbf
/opt/oracle/oradata/ora11g/sysaux01.dbf
/opt/oracle/oradata/ora11g/undotbs01.dbf
/opt/oracle/oradata/ora11g/users01.dbf
/opt/oracle/oradata/ora11g/example01.dbf

--删除example01.dbf数据文件
SQL> !rm /opt/oracle/oradata/ora11g/example01.dbf

SQL> !ls -l /opt/oracle/oradata/ora11g/example01.dbf
ls: /opt/oracle/oradata/ora11g/example01.dbf: 没有那个文件或目录

--因为数据文件被删除，创建表失败
SQL> create table t_xifenfei tablespace example
  2  as select * from dba_tables;
as select * from dba_tables
                 *
ERROR at line 2:
ORA-01116: error in opening database file 5
ORA-01110: data file 5: '/opt/oracle/oradata/ora11g/example01.dbf'
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3

二.找回数据文件

--查找dbw进程spid
[oracle@node1 ~]$ ps -ef|grep dbw|grep -v grep
oracle   18387     1  0 Dec22 ?        00:00:12 ora_dbw0_ora11g

--查看该进程所有文件句柄
[oracle@node1 ~]$ ll /proc/18387/fd
总计 0
lr-x------ 1 oracle oinstall 64 12-31 22:03 0 -> /dev/null
l-wx------ 1 oracle oinstall 64 12-31 22:03 1 -> /dev/null
lr-x------ 1 oracle oinstall 64 12-31 22:03 10 -> /dev/zero
lr-x------ 1 oracle oinstall 64 12-31 22:03 11 -> /dev/zero
lr-x------ 1 oracle oinstall 64 12-31 22:03 12 -> /opt/oracle/product/11.2.0/db_1/rdbms/mesg/orazhs.msb
lrwx------ 1 oracle oinstall 64 12-31 22:03 13 -> /opt/oracle/product/11.2.0/db_1/dbs/hc_ora11g.dat
lr-x------ 1 oracle oinstall 64 12-31 22:03 14 -> /proc/18387/fd
lr-x------ 1 oracle oinstall 64 12-31 22:03 15 -> /dev/zero
lr-x------ 1 oracle oinstall 64 12-31 22:03 16 -> /opt/oracle/product/11.2.0/db_1/rdbms/mesg/oraus.msb
lrwx------ 1 oracle oinstall 64 12-31 22:03 17 -> /opt/oracle/product/11.2.0/db_1/dbs/hc_ora11g.dat
lrwx------ 1 oracle oinstall 64 12-31 22:03 18 -> /opt/oracle/product/11.2.0/db_1/dbs/lkORA11G
lr-x------ 1 oracle oinstall 64 12-31 22:03 19 -> /opt/oracle/product/11.2.0/db_1/rdbms/mesg/orazhs.msb
l-wx------ 1 oracle oinstall 64 12-31 22:03 2 -> /dev/null
lr-x------ 1 oracle oinstall 64 12-31 22:03 20 -> /opt/oracle/product/11.2.0/db_1/rdbms/mesg/oraus.msb
lrwx------ 1 oracle oinstall 64 12-31 22:03 21 -> socket:[441562]
lrwx------ 1 oracle oinstall 64 12-31 22:03 256 -> /opt/oracle/oradata/ora11g/control01.ctl
lrwx------ 1 oracle oinstall 64 12-31 22:03 257 -> /opt/oracle/oradata/ora11g/system01.dbf
lrwx------ 1 oracle oinstall 64 12-31 22:03 258 -> /opt/oracle/oradata/ora11g/sysaux01.dbf
lrwx------ 1 oracle oinstall 64 12-31 22:03 259 -> /opt/oracle/oradata/ora11g/undotbs01.dbf
lrwx------ 1 oracle oinstall 64 12-31 22:03 260 -> /opt/oracle/oradata/ora11g/users01.dbf
lrwx------ 1 oracle oinstall 64 12-31 22:03 261 -> /opt/oracle/oradata/ora11g/example01.dbf (deleted)
lrwx------ 1 oracle oinstall 64 12-31 22:03 262 -> /opt/oracle/oradata/ora11g/temp01.dbf
lr-x------ 1 oracle oinstall 64 12-31 22:03 3 -> /dev/null
lr-x------ 1 oracle oinstall 64 12-31 22:03 4 -> /dev/null
lrwx------ 1 oracle oinstall 64 12-31 22:03 5 -> /opt/oracle/product/11.2.0/db_1/dbs/hc_ora11g.dat
lr-x------ 1 oracle oinstall 64 12-31 22:03 6 -> /dev/null
lr-x------ 1 oracle oinstall 64 12-31 22:03 7 -> /dev/null
lr-x------ 1 oracle oinstall 64 12-31 22:03 8 -> /dev/null
lr-x------ 1 oracle oinstall 64 12-31 22:03 9 -> /dev/null
--通过句柄恢复数据文件[被删除数据文件会被标示(deleted)]
[oracle@node1 ~]$ cp /proc/18387/fd/261 /opt/oracle/oradata/ora11g/example01.dbf
--确认该数据文件已经恢复成功
[oracle@node1 ~]$ ll /opt/oracle/oradata/ora11g/example01.dbf
-rw-r----- 1 oracle oinstall 362422272 12-31 22:05 /opt/oracle/oradata/ora11g/example01.dbf

三.数据文件online

SQL> alter database datafile 5 offline;
 
Database altered.
 
SQL> recover datafile 5;
Media recovery complete.
SQL> alter database datafile 5 online;
 
Database altered.

SQL> create table t_xifenfei tablespace example
  2  as select * from dba_tables;

Table created.

四.补充说明
在意外使用os命令删除掉数据文件时，千万不要慌张重启数据库或者操作系统，可以通过dbwn进程相关句柄找回数据文件

Linux中文件大小限制

Posted on 2011 年 12 月 18 日 by 惜分飞

在日常的维护中，偶尔总担心某个文件会不会因为太大(超过系统限制大小)，导致工作不正常。查找了一些资料，这里对文件大小限制的情况做个记录，以便以后做到心中有底
一、文件大小限制列表

二、查看数据块大小
1、直接查看操作磁盘(Block size)

[root@bas ~]# tune2fs -l /dev/sda2
tune2fs 1.35 (28-Feb-2004)
Filesystem volume name:   /home
…………
Block size:               4096
Fragment size:            4096
…………
Journal backup:           inode blocks

2、查看某个文件(IO Block)

[oracle@bas backup]$ stat full_back.dmp 
  File: `full_back.dmp'
  Size: 429687808000    Blocks: 840054384  IO Block: 4096   regular file
Device: 812h/2066d      Inode: 13          Links: 1
Access: (0644/-rw-r--r--)  Uid: (  501/  oracle)   Gid: (  501/oinstall)
Access: 2011-12-18 02:00:25.000000000 +0800
Modify: 2011-12-18 20:49:31.000000000 +0800
Change: 2011-12-18 20:49:31.000000000 +0800

Linux重设root密码

Posted on 2011 年 12 月 13 日 by 惜分飞

今天去省公安厅部署系统，那边没有网络，不用使用自己的电脑，突然发现原来网络是那么的美好，原来自己电脑上的资料是那么的珍贵；也发现一个问题，做技术的要坦实，是实实在在的懂，而不是说我有个了解，然后google下就可以了。今天就遇到有Linux服务器root密码忘记了，因为sa没有过去，开发不懂，只能我去重设，因为以前这些活都是sa做的，自己有所了解但是记忆不深，今天在自己的大脑中拼命的搜索，不断的尝试，终于修改成功了。晚上回家在vm中做了linux 4/5/6三个版本的修改密码方法截，给自己留个记录，也供大家参考，免得临时手忙脚乱
Linux重设root密码

Linux之pmap命令

Posted on 2011 年 11 月 03 日 by 惜分飞

观察数据库发现，ora_dbw进程占用内存非常高，感觉很奇怪，然后询问高手，通过pmap命令发现，该进程是几乎具有了整个sga的句柄，所以显示占用的内存非常大，其实自己私有的很小

[oracle@DB1 ~]$ top -c

top – 23:06:02 up 553 days, 21:46, 1 user, load average: 0.62, 0.58, 0.47

Tasks: 365 total, 1 running, 364 sleeping, 0 stopped, 0 zombie

Cpu(s): 0.7%us, 0.3%sy, 0.0%ni, 98.3%id, 0.5%wa, 0.0%hi, 0.2%si, 0.0%st

Mem: 24666528k total, 24504356k used, 162172k free, 9192k buffers

Swap: 24579440k total, 3864056k used, 20715384k free, 18728188k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

2270 oracle 15 -1 20.1g 1.1g 1.1g S 2.7 4.7 147:10.01 oracleora9i (LOCAL=NO)

4334 oracle 14 -1 20.1g 1.7g 1.7g S 1.3 7.4 3:08.38 oracleora9i (LOCAL=NO)

5491 oracle 15 -1 20.2g 14g 14g S 1.3 62.1 699:54.55 ora_dbw1_ora9i

9682 oracle 15 0 12868 1296 820 R 1.3 0.0 0:00.14 top -c

18552 oracle 14 -1 20.1g 1.7g 1.7g S 1.3 7.2 2:43.74 oracleora9i (LOCAL=NO)

29977 oracle 14 -1 20.1g 2.1g 2.1g S 1.3 9.1 4:50.87 oracleora9i (LOCAL=NO)

SQL> show parameter sga;

NAME TYPE VALUE

———————————— ———– ——————————

lock_sga boolean FALSE

pre_page_sga boolean FALSE

sga_max_size big integer 20G

sga_target big integer 20G

[oracle@DB1 ~]$ pmap

Usage: pmap [-x | -d] [-q] pid…

-x show details

-d show offset and device number

-q quiet; less header/footer info

-V show the version number

[oracle@DB1 ~]$ pmap -d 5491

5491: ora_dbw1_ora9i

Address Kbytes Mode Offset Device Mapping

0000000000400000 100412 r-x– 0000000000000000 008:00005 oracle

000000000680f000 544 rwx– 000000000620f000 008:00005 oracle

0000000006897000 148 rwx– 0000000006897000 000:00000 [ anon ]

000000001f2f7000 596 rwx– 000000001f2f7000 000:00000 [ anon ]

0000000060000000 20971520 rwxs- 0000000000000000 000:00009 [ shmid=0x0 ]

0000000580000000 2048 rwxs- 0000000000000000 000:00009 [ shmid=0x8001 ]

0000003b44a00000 112 r-x– 0000000000000000 008:00001 ld-2.5.so

……

00002b293c72b000 64 rwx– 0000000000000000 000:00011 zero

00002b293c73b000 64 rwx– 0000000000000000 000:00011 zero

00002b293c74b000 64 rwx– 0000000000000000 000:00011 zero

00002b293c75b000 3840 —– 0000000000b2a000 000:00011 zero

00007fff710f7000 84 rwx– 00007ffffffea000 000:00000 [ stack ]

ffffffffff600000 8192 —– 0000000000000000 000:00000 [ anon ]

mapped: 21145976K writeable/private: 19316K shared: 20973572K

[oracle@DB1 ~]$ pmap -x 5491

5491: ora_dbw1_ora9i

Address Kbytes RSS Anon Locked Mode Mapping

0000000000400000 100412 – – – r-x– oracle

000000000680f000 544 – – – rwx– oracle

0000000006897000 148 – – – rwx– [ anon ]

000000001f2f7000 596 – – – rwx– [ anon ]

0000000060000000 20971520 – – – rwxs- [ shmid=0x0 ]

0000000580000000 2048 – – – rwxs- [ shmid=0x8001 ]

……

00002b293c73b000 64 – – – rwx– zero

00002b293c74b000 64 – – – rwx– zero

00002b293c75b000 3840 – – – —– zero

00007fff710f7000 84 – – – rwx– [ stack ]

ffffffffff600000 8192 – – – —– [ anon ]

—————- —— —— —— ——

total kB 21145976 – – –

Address:进程所占的地址空间

Kbytes 该虚拟段的大小

RSS 设备号（主设备：次设备）

Anon 设备的节点号，0表示没有节点与内存相对应

Locked 是否允许swapped

Mode 权限：r=read, w=write, x=execute, s=shared, p=private(copy on write)

Mapping: bash 对应的映像文件名

13429648788

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Category Archives: Linux

dd操作数据文件

恢复被rm意外删除数据文件

Linux中文件大小限制

Linux重设root密码

Linux之pmap命令

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