[20151116]rman 全备份以及增量0级备份.txt

--前一阵子写了一篇将as copy作为增量0级备份的帖子，今天对比全备份以及增量0级备份的不同。

1.测试环境：
SCOTT@book> @ &r/ver1
PORT_STRING                    VERSION        BANNER
------------------------------ -------------- --------------------------------------------------------------------------------
x86_64/Linux 2.4.xx            11.2.0.4.0     Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

--设置表空间只读，为了比较的方便：

SCOTT@book> alter tablespace example read only ;
Tablespace altered.

--为了测试方便清除全部备份级以及copy备份。

RMAN> backup datafile 5  format '/home/oracle/backup/full_example_%u.dbf' tag='FULL';

Starting backup at 2015-11-16 16:21:15
using channel ORA_DISK_1
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00005 name=/mnt/ramdisk/book/example01.dbf
channel ORA_DISK_1: starting piece 1 at 2015-11-16 16:21:15
channel ORA_DISK_1: finished piece 1 at 2015-11-16 16:21:16
piece handle=/home/oracle/backup/full_example_3uqmdtrr.dbf tag=FULL comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 2015-11-16 16:21:16

RMAN> backup incremental level 0 datafile 5  format '/home/oracle/backup/inc0_example_%u.dbf' TAG='INC0';

Starting backup at 2015-11-16 16:21:28
using channel ORA_DISK_1
channel ORA_DISK_1: starting incremental level 0 datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00005 name=/mnt/ramdisk/book/example01.dbf
channel ORA_DISK_1: starting piece 1 at 2015-11-16 16:21:29
channel ORA_DISK_1: finished piece 1 at 2015-11-16 16:21:30
piece handle=/home/oracle/backup/inc0_example_3vqmdts9.dbf tag=INC0 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 2015-11-16 16:21:30

--查看文件：
]$ ls -l /home/oracle/backup/[fi]*example*.dbf
-rw-r----- 1 oracle oinstall 72187904 2015-11-16 16:21:15 /home/oracle/backup/full_example_3uqmdtrr.dbf
-rw-r----- 1 oracle oinstall 72187904 2015-11-16 16:21:29 /home/oracle/backup/inc0_example_3vqmdts9.dbf

--可以发现2个文件大小一致。

2.比较：
--先转换成ascii文件：

$  hexdump  -C full_example_3uqmdtrr.dbf > full.txt
$  hexdump  -C inc0_example_3vqmdts9.dbf > inc0.txt

$ diff  full.txt inc0.txt
7,8c7,8
< 00002010  98 6f 00 00 00 04 20 0b  00 04 20 0b 45 8b 9b 4f  |.o.... ... .E..O|
< 00002020  42 4f 4f 4b 00 00 00 00  e2 24 00 00 00 00 00 00  |BOOK....?......|
---
> 00002010  63 08 00 00 00 04 20 0b  00 04 20 0b 45 8b 9b 4f  |c..... ... .E..O|
            ~~~~~
> 00002020  42 4f 4f 4b 00 00 00 00  eb 24 00 00 00 00 00 00  |BOOK....?......|
12,13c12,13
< 00002060  01 00 00 00 7b f7 66 35  7e 00 00 00 01 00 00 00  |....{鱢5~.......|
< 00002070  01 00 00 00 46 55 4c 4c  00 00 00 00 00 00 00 00  |....FULL........|
---
> 00002060  01 00 00 00 89 f7 66 35  7f 00 00 00 01 00 00 00  |.....鱢5........|
                        ~~           ~~
> 00002070  01 00 00 00 49 4e 43 30  00 00 00 00 00 00 00 00  |....INC0........|
                        ~~~~~~~~~~~
                        tag不同比较容易发现
15c15
< 00002090  00 00 00 00 04 04 00 00  4b 01 00 00 03 a5 00 00  |........K....?.|
---
> 00002090  00 00 00 00 05 04 00 00  4b 01 00 00 03 a5 00 00  |........K....?.|
                        ~~

--注意仅仅标识~ 的部分不同。
SCOTT@book> @ &r/16to10 2010
16 to 10 DEC
------------
        8208

SCOTT@book> @ &r/16to10 2090
16 to 10 DEC
------------
        8336

--如果以8k作为1个块，仅仅第2块不同。

RMAN> list backupset ;

List of Backup Sets
===================

BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ -------------------
116     Full    68.84M     DISK        00:00:00     2015-11-16 16:21:15
        BP Key: 116   Status: AVAILABLE  Compressed: NO  Tag: FULL
        Piece Name: /home/oracle/backup/full_example_3uqmdtrr.dbf
  List of Datafiles in backup set 116
  File LV Type Ckp SCN    Ckp Time            Name
  ---- -- ---- ---------- ------------------- ----
  5       Full 1774661    2015-11-16 16:16:33 /mnt/ramdisk/book/example01.dbf

BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ -------------------
117     Incr 0  68.84M     DISK        00:00:00     2015-11-16 16:21:29
        BP Key: 117   Status: AVAILABLE  Compressed: NO  Tag: INC0
        Piece Name: /home/oracle/backup/inc0_example_3vqmdts9.dbf
  List of Datafiles in backup set 117
  File LV Type Ckp SCN    Ckp Time            Name
  ---- -- ---- ---------- ------------------- ----
  5    0  Incr 1774661    2015-11-16 16:16:33 /mnt/ramdisk/book/example01.dbf

--除了tag标识比较容易识别外，其它看不出来。
--116 = 0x74  1774661 = 0x1b1445

3.感觉两者差别不大，不过rman的catalog命令并不能把full备份的备份集换成增量备份集。

RMAN> catalog backuppiece "/home/oracle/backup/full_example_3uqmdtrr.dbf" level 0;
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00558: error encountered while parsing input commands
RMAN-01009: syntax error: found "level": expecting one of: "comma, ;"
RMAN-01007: at line 1 column 69 file: standard input

--晚上正好看了链接：http://www.pythian.com/blog/rman-full-backup-level-0-incrmental/
What might these mean?
Here’s a possible explanation:

0x2094 = 0x04 = FULL
0x2094 = 0x05 = Incremental

0x2095 = 0x04 = level 0 if the previous byte is 0x05
0x2095 = 0x00 = level 1 if the previous byte is 0x05

---如果我改动偏移0x2094=0x05 是否可以变成增量呢？测试看看。

4.继续测试：

RMAN> change backuppiece "/home/oracle/backup/full_example_3uqmdtrr.dbf" uncatalog ;
uncataloged backup piece
backup piece handle=/home/oracle/backup/full_example_3uqmdtrr.dbf RECID=116 STAMP=895940475
Uncataloged 1 objects

$  bvi -b 0 -s 16384 full_example_3uqmdtrr.dbf

-- 改动偏移0x2094 ,0x04=>0x05.

-- 使用bbed修改检查和。
BBED> set dba 20,1
        DBA             0x05000001 (83886081 20,1)

BBED> sum
Check value for File 20, Block 1:
current = 0x6f98, required = 0x6f99

BBED> sum apply
Check value for File 20, Block 1:
current = 0x6f99, required = 0x6f99
--注：从这里可以推出：0x2010 处是 检查和。
--注： 如果不改检查和，会报错：
RMAN> catalog backuppiece "/home/oracle/backup/full_example_3uqmdtrr.dbf" ;
ORA-19870: error while restoring backup piece /home/oracle/backup/full_example_3uqmdtrr.dbf
ORA-19608: /home/oracle/backup/full_example_3uqmdtrr.dbf is not a backup piece
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of catalog command at 11/17/2015 08:21:01
RMAN-06209: List of failed objects
RMAN-06211: ==========================
RMAN-06212:   Object Type   Filename/Handle
RMAN-06213: --------------- ---------------------------------------------------
RMAN-06214: Backup Piece    /home/oracle/backup/full_example_3uqmdtrr.dbf
--------------------

RMAN> catalog backuppiece "/home/oracle/backup/full_example_3uqmdtrr.dbf" ;
cataloged backup piece
backup piece handle=/home/oracle/backup/full_example_3uqmdtrr.dbf RECID=118 STAMP=895998477

--OK注册成功！RECID=118

RMAN> list backupset ;
List of Backup Sets
===================
BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ -------------------
117     Incr 0  68.84M     DISK        00:00:00     2015-11-16 16:21:29
        BP Key: 117   Status: AVAILABLE  Compressed: NO  Tag: INC0
        Piece Name: /home/oracle/backup/inc0_example_3vqmdts9.dbf
  List of Datafiles in backup set 117
  File LV Type Ckp SCN    Ckp Time            Name
  ---- -- ---- ---------- ------------------- ----
  5    0  Incr 1774661    2015-11-16 16:16:33 /mnt/ramdisk/book/example01.dbf

BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ -------------------
118     Incr 0  68.84M     DISK        00:00:00     2015-11-16 16:21:15
        BP Key: 118   Status: AVAILABLE  Compressed: NO  Tag: FULL
        Piece Name: /home/oracle/backup/full_example_3uqmdtrr.dbf
  List of Datafiles in backup set 118
  File LV Type Ckp SCN    Ckp Time            Name
  ---- -- ---- ---------- ------------------- ----
  5       Full 1774661    2015-11-16 16:16:33 /mnt/ramdisk/book/example01.dbf

--注意看BS_KEY=118 的TAG=FULL.

--验证看看是否可以使用：
RMAN> change backuppiece tag INC0 uncatalog;
uncataloged backup piece
backup piece handle=/home/oracle/backup/inc0_example_3vqmdts9.dbf RECID=117 STAMP=895940489
Uncataloged 1 objects

RMAN> restore datafile 5 preview;
Starting restore at 2015-11-17 08:44:55
using channel ORA_DISK_1

List of Backup Sets
===================
BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ -------------------
118     Incr 0  68.84M     DISK        00:00:00     2015-11-16 16:21:15
        BP Key: 118   Status: AVAILABLE  Compressed: NO  Tag: FULL
        Piece Name: /home/oracle/backup/full_example_3uqmdtrr.dbf
  List of Datafiles in backup set 118
  File LV Type Ckp SCN    Ckp Time            Name
  ---- -- ---- ---------- ------------------- ----
  5       Full 1774661    2015-11-16 16:16:33 /mnt/ramdisk/book/example01.dbf
Finished restore at 2015-11-17 08:44:55

RMAN> recover datafile 5 preview;

Starting recover at 2015-11-17 08:45:01
using channel ORA_DISK_1
using channel ORA_DISK_1

List of Archived Log Copies for database with db_unique_name BOOK
=====================================================================

Key     Thrd Seq     S Low Time
------- ---- ------- - -------------------
37      1    43      A 2015-11-14 10:07:15
        Name: /u01/app/oracle/archivelog/book/1_43_894797959.dbf

Media recovery start SCN is 1774661
Recovery must be done beyond SCN 1774661 to clear datafile fuzziness
Finished recover at 2015-11-17 08:45:01

--至少验证通过，说明full备份与0级备份文件差别不大，仅仅存在细微的差别。
--说实在知道这些没有意义，仅仅做一些简单探究。