一、测试目标
疑问？ 我们都知道Oracle RAC使用ASM管理存储；
对于ASM磁盘组而言冗余模式有三种，EXTERN、NORMALN、HIGH，那么这三种冗余方式有什么作用呢？
假设磁盘损坏，能丢失多少块磁盘呢？？？
我们在来推断一下这个东西有什么使用场景！ASM磁盘组是否值得多配置存储，配置冗余模式。
本篇文档，带着这些疑问，进行测试，并进行汇总整理思路，实现自问自答。 本次测试不考虑ocr磁盘组，只测试DATA磁盘组进行思考。
二、Oracle ASM磁盘组的冗余策略
EXTERN 磁盘组无冗余,丢失1块磁盘,磁盘组dismount，磁盘组无法对外提供正常的读写；
NORMAL磁盘组数据写2份，一份主数据，一份备份copy数据，丢失1块磁盘磁盘组正常，最多丢失同一个failgroup组的所有磁盘；
HIGH 磁盘组数据写3份，一份主数据，另外2份备份copy数据，丢失2块磁盘磁盘组正常，最多丢失两组failgroup组的所有磁盘；
Oracle ASM磁盘为什么需要配置冗余？ 底层操作系统RAID 10,5不香吗？ 是否多此一举。
正是有着操作系统RAID,因此目前运维驻场的客户这边，绝大部分DATA磁盘组均为extern非冗余！ 但是这种场景无法进行机房级别的容灾，整个机房掉电、其它异常导致无法访问！ 即使操作系统存储RAID无效果。
如果使用NORMAL，2份存储，一份存储A机房，另外一份存储B机房，分别属于2个FAILGROUP组，A机房异常，不影响RAC DB的服务！
三、实验测试
第一阶段：测试实验DATA1 EXTERN情况下,观察failgroup情况；
第二阶段：测试实验DATA2 NORMALN情况下,3块磁盘，观察failgroup情况；
第三阶段：测试实验DATA2 NORMALN情况下,6块磁盘，观察failgroup情况；
第四阶段：测试实验DATA2 HIGH情况下，6块磁盘，观察failgroup情况；
第一阶段：测试实验DATA1 EXTERN情况下,观察failgroup情况；
SQL> select name,type from v$asm_diskgroup; NAME TYPE ------------------------------------------------------------------------------------------ ------------------ DATA1 EXTERN SQL> select group_number,disk_number,state,failgroup,path from v$asm_disk where group_number=2 order by 2; GROUP_NUMBER DISK_NUMBER STATE FAILGROUP PATH ------------ ----------- ----------- ------------------------ -------------------- ---------------------------- 2 0 NORMAL DATA1_0000 /dev/oracleasm/disks/ASMDISK10 2 1 NORMAL DATA1_0001 /dev/oracleasm/disks/ASMDISK11 2 2 NORMAL DATA1_0002 /dev/oracleasm/disks/ASMDISK12 2 3 NORMAL DATA1_0003 /dev/oracleasm/disks/ASMDISK7 2 4 NORMAL DATA1_0004 /dev/oracleasm/disks/ASMDISK8 2 5 NORMAL DATA1_0005 /dev/oracleasm/disks/ASMDISK9 2 6 NORMAL DATA1_0006 /dev/oracleasm/disks/ASMDISK13 7 rows selected. extenal冗余：
--------ASM是以AU为分配单位，1个AU为1M，这里创建一个大小为14M的表空间，理论上讲应该分配了14个区.
SQL> create tablespace gao1 datafile '+DATA1' size 14m;
SQL> create table gaogaogago(id number(20)) tablespace GAO1;
SQL> select file_number,name from v$asm_alias where name like 'GAO%';
FILE_NUMBER NAME
----------- --------------------------
283 GAO1.283.1057142127
v$asm_alias视图字段解释: Column Name Description NUMBER_KFFXP ASM file number.
Join with v$asm_file and v$asm_alias COMPOUND_KFFXP File identifier.
Join with compound_index in v$asm_file INCARN_KFFXP File incarnation id.
Join with incarnation in v$asm_file XNUM_KFFXP ASM file extent number (mirrored extent pairs have the same extent value) PXN_KFFXP Progressive file extent number GROUP_KFFXP ASM disk group number.
Join with v$asm_disk and v$asm_diskgroup DISK_KFFXP ASM disk number.
Join with v$asm_disk AU_KFFXP Relative position of the allocation unit from the beginning of the disk.
LXN_KFFXP 0->primary extent,1->mirror extent,
2->2nd mirror copy (high redundancy and metadata)
DISK_KFFXP：对应v$asm_disk.DISK_NUMBER
NUMBER_KFFXP：对应v$asm_file.FILE_NUMBER
XNUM_KFFXP:ASM文件的extent号
select disk_kffxp disk#, XNUM_KFFXP extent#,
case lxn_kffxp
when 0 then 'Primary Copy'
when 1 then 'Mirrored Copy'
when 2 then '2nd Mirrored Copy or metadata' else 'Unknown'
END TYPE
from x$kffxp
where number_kffxp=283 order by 2;
ASM是以AU为分配单位，1个AU为1M，这里创建一个大小为14M的表空间，分配了14个区.由下面结果可已看到一共14个区，都为primary copy，并没有mirror copy，也就是说external是只存一份数据的。
DISK# EXTENT# TYPE
---------- ---------- ------------------
0 0 Primary Copy
2 0 Primary Copy
0 1 Primary Copy
6 1 Primary Copy
0 2 Primary Copy
5 2 Primary Copy
4 3 Primary Copy
0 4 Primary Copy
1 5 Primary Copy
3 6 Primary Copy
2 7 Primary Copy
6 8 Primary Copy
5 9 Primary Copy
4 10 Primary Copy
0 11 Primary Copy
1 12 Primary Copy
3 13 Primary Copy
2 14 Primary Copy
18 rows selected.
第二阶段：测试实验DATA2 NORMALN情况下,3块磁盘，观察failgroup情况；
删除表空间gao1,然后创建表空间gao1，指定ASM磁盘组为+DATA2(NORMAL冗余磁盘组) SQL> drop tablespace gao1 including contents and datafiles; select group_number,name,TOTAL_MB,free_mb,type from v$asm_diskgroup; GROUP_NUMBER NAME TOTAL_MB FREE_MB TYPE ------------ ------------------------------ ---------- ---------- ------ 2 DATA1 17129 53 EXTERN 3 DATA2 7341 7005 NORMAL SQL> select group_number,name,disk_number,failgroup_type,path,failgroup from v$asm_disk where group_number=3 GROUP_NUMBER NAME DISK_NUMBER FAILGROUP_TYPE PATH FAILGROUP ------------ -------------------- ----------- --------------------- ---------------------------------------- -------------------- 3 DATA2_0002 2 REGULAR /dev/oracleasm/disks/ASMDISK6 DATA2_0002 3 DATA2_0001 1 REGULAR /dev/oracleasm/disks/ASMDISK5 DATA2_0001 3 DATA2_0000 0 REGULAR /dev/oracleasm/disks/ASMDISK4 DATA2_0000 create tablespace GAO1 datafile '+DATA2' size 14m; select file_number,name from v$asm_alias where name like 'GAO%'; FILE_NUMBER NAME ----------- ------------------------------------------------------------- 257 GAO1.257.1057145865 grid$sqlplus / as sysdba select GROUP_KFFXP,disk_kffxp disk#, XNUM_KFFXP extent#, case lxn_kffxp when 0 then 'Primary Copy' when 1 then 'Mirrored Copy' when 2 then '2nd Mirrored Copy or metadata' else 'Unknown' END TYPE from x$kffxp where number_kffxp=257 and GROUP_KFFXP=3 order by 1,2,3; 由下图可见，所有的数据都是有两份的:Primary Copy 和Mirrored Copy，然后每个区的数据都是被分散在三个failgroup中的，所以无论哪个failgroup里面的磁盘坏了，都不会丢数据，但是只允许同时损坏同一个failgroup里面的磁盘 GROUP_KFFXP DISK# EXTENT# TYPE ----------- ---------- ---------- ------------------------------ Failgroup1 3 0 1 Primary Copy 3 0 2 Mirrored Copy 3 0 3 Mirrored Copy 3 0 4 Primary Copy 3 0 7 Primary Copy 3 0 8 Mirrored Copy 3 0 9 Mirrored Copy 3 0 10 Primary Copy 3 0 13 Primary Copy 3 0 14 Mirrored Copy Failgroup2 3 1 0 Primary Copy 3 1 3 Primary Copy 3 1 4 Mirrored Copy 3 1 5 Mirrored Copy 3 1 6 Primary Copy 3 1 9 Primary Copy 3 1 10 Mirrored Copy 3 1 11 Mirrored Copy 3 1 12 Primary Copy Failgroup3 3 2 0 Mirrored Copy 3 2 1 Mirrored Copy 3 2 2 Primary Copy 3 2 5 Primary Copy 3 2 6 Mirrored Copy 3 2 7 Mirrored Copy 3 2 8 Primary Copy 3 2 11 Primary Copy 3 2 12 Mirrored Copy 3 2 13 Mirrored Copy 3 2 14 Primary Copy 30 rows selected.
大家细心对比，可以发现，丢失任何FAILGROUP的2块磁盘都没了，但是DB无异常，在其它两个FAILGROUP都存在记录。
第三阶段：测试实验DATA2 NORMALN情况下,6块磁盘，观察failgroup情况；
将DATA1磁盘删除3块，添加至DATA2磁盘组！ select group_number,disk_number,name,failgroup,total_mb,free_mb,path,mount_status,header_status,mode_status,state from v$asm_disk order by 1,2,3 GROUP_NUMBER DISK_NUMBER NAME FAILGROUP TOTAL_MB FREE_MB PATH MOUNT_STAT HEADER_STA MODE_STATU STATE ------------ ----------- ------------ -------- ---------- ---------- ---------- ----------------------------------- ---------- ---------- ---------- ------------------------ 1 0 ARCH_0000 ARCH_0000 4016 1635 /dev/oracleasm/disks/ASMDISK14 CACHED MEMBER ONLINE NORMAL 2 0 DATA1_0000 DATA1_0000 2447 45 /dev/oracleasm/disks/ASMDISK10 CACHED MEMBER ONLINE NORMAL 2 1 DATA1_0001 DATA1_0001 2447 50 /dev/oracleasm/disks/ASMDISK11 CACHED MEMBER ONLINE NORMAL 2 2 DATA1_0002 DATA1_0002 2447 50 /dev/oracleasm/disks/ASMDISK12 CACHED MEMBER ONLINE NORMAL 2 3 DATA1_0003 DATA1_0003 2447 45 /dev/oracleasm/disks/ASMDISK7 CACHED MEMBER ONLINE NORMAL 2 4 DATA1_0004 DATA1_0004 2447 55 /dev/oracleasm/disks/ASMDISK8 CACHED MEMBER ONLINE NORMAL 2 5 DATA1_0005 DATA1_0005 2447 50 /dev/oracleasm/disks/ASMDISK9 CACHED MEMBER ONLINE NORMAL 2 6 DATA1_0006 DATA1_0006 2447 51 /dev/oracleasm/disks/ASMDISK13 CACHED MEMBER ONLINE NORMAL 3 0 DATA2_0000 DATA2_0000 2447 2335 /dev/oracleasm/disks/ASMDISK4 CACHED MEMBER ONLINE NORMAL 3 1 DATA2_0001 DATA2_0001 2447 2336 /dev/oracleasm/disks/ASMDISK5 CACHED MEMBER ONLINE NORMAL 3 2 DATA2_0002 DATA2_0002 2447 2334 /dev/oracleasm/disks/ASMDISK6 CACHED MEMBER ONLINE NORMAL 5 0 OCR_0000 OCR_0000 2447 2138 /dev/oracleasm/disks/ASMDISK1 CACHED MEMBER ONLINE NORMAL 5 1 OCR_0001 OCR_0001 2447 2139 /dev/oracleasm/disks/ASMDISK2 CACHED MEMBER ONLINE NORMAL 5 2 OCR_0002 OCR_0002 2447 2138 /dev/oracleasm/disks/ASMDISK3 CACHED MEMBER ONLINE NORMAL 14 rows selected.
删除磁盘失败，提示剩余的空间不满足rebalance,后续手工删除table数据，有用的表move,索引rebuild;后resize 数据文件，回收空间。
alter diskgroup DATA1 drop disk 'DATA1_0006','DATA1_0005','DATA1_0004' REBALANCE POWER 0;
ORA-15032: not all alterations performed
ORA-15250: insufficient diskgroup space for rebalance completion
SQL> select sum(bytes)/1024/1024/1024,owner from dba_segments group by owner order by 1;
.280517578 SH
1.43621826 SYS
2.13165283 SCOTT
3.82910156 TEST
drop user test cascade;
SQL> select tablespace_name,file_name,bytes/1024/1024/1024,file_id from dba_data_files order by 1,2,3;
TABLESPACE_NAME FILE_NAME BYTES/1024/1024/1024
------------------------------ -------------------------------------------------- -------------------- ----------
USERS +DATA1/dr2_prod4/datafile/users.258.1057140291 10.7202148 4
SQL> select name,total_mb,free_mb from v$asm_diskgroup where name='DATA1';
NAME TOTAL_MB FREE_MB
------------------------------ ---------- ----------
DATA1 17129 346
alter database datafile '+DATA1/dr2_prod4/datafile/users.258.1057140291' resize 1g;
ORA-03297: file contains used data beyond requested RESIZE value
找到block_id 大的，处于file后半段进行处理
select owner,segment_name,tablespace_name,bytes/1024/1024,EXTENT_ID,FILE_ID,block_id from dba_extents where tablespace_name='USERS' AND FILE_ID=4 order by EXTENT_ID;
OE SYS_C0011258 USERS .0625 0 4 512
SCOTT DEPT_BAK USERS .0625 0 4 508144
SCOTT DEPT1 USERS .0625 0 4 508152
OE SYS_C0011258 USERS .0625 0 4 512
SCOTT DEPT_BAK USERS .0625 0 4 508144
SCOTT DEPT1 USERS .0625 0 4 508152
GAO TEST USERS .0625 0 4 315984
alter table SCOTT.DEPT_BAK move;
alter table SCOTT.DEPT1 move;
alter table GAO.TEST move;
alter index SCOTT.PK_DEPT1 rebuild;
drop table test01.a purge;
alter database datafile 4 resize 1g;
NAME TOTAL_MB FREE_MB
------------------------------ ---------- ----------
DATA1 17129 10299
alter diskgroup DATA1 drop disk 'DATA1_0006','DATA1_0005','DATA1_0004' REBALANCE POWER 0;
col mount_status for a10
col header_status for a10
col mode_status for a10
col state for a10
select group_number,disk_number,name,failgroup,total_mb,free_mb,path,mount_status,header_status,mode_status,state from v$asm_disk order by 1,2,3;
GROUP_NUMBER DISK_NUMBER NAME FAILGROUP TOTAL_MB FREE_MB PATH MOUNT_STAT HEADER_STA MODE_STATU STATE
------------ ----------- ---------- ---------- ---------- ---------- ------------------------------ ---------- ---------- ---------- ----------
1 0 ARCH_0000 ARCH_0000 4016 1635 /dev/oracleasm/disks/ASMDISK14 CACHED MEMBER ONLINE NORMAL
2 0 DATA1_0000 DATA1_0000 2447 1467 /dev/oracleasm/disks/ASMDISK10 CACHED MEMBER ONLINE NORMAL
2 1 DATA1_0001 DATA1_0001 2447 1472 /dev/oracleasm/disks/ASMDISK11 CACHED MEMBER ONLINE NORMAL
2 2 DATA1_0002 DATA1_0002 2447 1472 /dev/oracleasm/disks/ASMDISK12 CACHED MEMBER ONLINE NORMAL
2 3 DATA1_0003 DATA1_0003 2447 1467 /dev/oracleasm/disks/ASMDISK7 CACHED MEMBER ONLINE NORMAL
2 4 DATA1_0004 DATA1_0004 2447 1476 /dev/oracleasm/disks/ASMDISK8 CACHED MEMBER ONLINE DROPPING
2 5 DATA1_0005 DATA1_0005 2447 1472 /dev/oracleasm/disks/ASMDISK9 CACHED MEMBER ONLINE DROPPING
2 6 DATA1_0006 DATA1_0006 2447 1473 /dev/oracleasm/disks/ASMDISK13 CACHED MEMBER ONLINE DROPPING
3 0 DATA2_0000 DATA2_0000 2447 2335 /dev/oracleasm/disks/ASMDISK4 CACHED MEMBER ONLINE NORMAL
3 1 DATA2_0001 DATA2_0001 2447 2336 /dev/oracleasm/disks/ASMDISK5 CACHED MEMBER ONLINE NORMAL
3 2 DATA2_0002 DATA2_0002 2447 2334 /dev/oracleasm/disks/ASMDISK6 CACHED MEMBER ONLINE NORMAL
5 0 OCR_0000 OCR_0000 2447 2138 /dev/oracleasm/disks/ASMDISK1 CACHED MEMBER ONLINE NORMAL
5 1 OCR_0001 OCR_0001 2447 2139 /dev/oracleasm/disks/ASMDISK2 CACHED MEMBER ONLINE NORMAL
5 2 OCR_0002 OCR_0002 2447 2138 /dev/oracleasm/disks/ASMDISK3 CACHED MEMBER ONLINE NORMAL
14 rows selected.
被删除drop的磁盘STATE =DROPPING
alter diskgroup data1 rebalance power 6;
select * from v$asm_operation;
GROUP_NUMBER OPERATION STATE POWER ACTUAL SOFAR EST_WORK EST_RATE EST_MINUTES ERROR_CODE
------------ --------------- ---------- ---------- ---------- ---------- ---------- ---------- ----------- --------------------
2 REBAL RUN 6 6 2465 3384 5602 0
GROUP_NUMBER DISK_NUMBER NAME FAILGROUP TOTAL_MB FREE_MB PATH MOUNT_STAT HEADER_STA MODE_STATU STATE
------------ ----------- ---------- ---------- ---------- ---------- ------------------------------ ---------- ---------- ---------- ----------
0 0 0 0 /dev/oracleasm/disks/ASMDISK13 CLOSED FORMER ONLINE NORMAL
0 1 0 0 /dev/oracleasm/disks/ASMDISK9 CLOSED FORMER ONLINE NORMAL
0 2 0 0 /dev/oracleasm/disks/ASMDISK8 CLOSED FORMER ONLINE NORMAL
1 0 ARCH_0000 ARCH_0000 4016 1635 /dev/oracleasm/disks/ASMDISK14 CACHED MEMBER ONLINE NORMAL
2 0 DATA1_0000 DATA1_0000 2447 741 /dev/oracleasm/disks/ASMDISK10 CACHED MEMBER ONLINE NORMAL
2 1 DATA1_0001 DATA1_0001 2447 740 /dev/oracleasm/disks/ASMDISK11 CACHED MEMBER ONLINE NORMAL
2 2 DATA1_0002 DATA1_0002 2447 743 /dev/oracleasm/disks/ASMDISK12 CACHED MEMBER ONLINE NORMAL
2 3 DATA1_0003 DATA1_0003 2447 740 /dev/oracleasm/disks/ASMDISK7 CACHED MEMBER ONLINE NORMAL
3 0 DATA2_0000 DATA2_0000 2447 2335 /dev/oracleasm/disks/ASMDISK4 CACHED MEMBER ONLINE NORMAL
3 1 DATA2_0001 DATA2_0001 2447 2336 /dev/oracleasm/disks/ASMDISK5 CACHED MEMBER ONLINE NORMAL
3 2 DATA2_0002 DATA2_0002 2447 2334 /dev/oracleasm/disks/ASMDISK6 CACHED MEMBER ONLINE NORMAL
5 0 OCR_0000 OCR_0000 2447 2138 /dev/oracleasm/disks/ASMDISK1 CACHED MEMBER ONLINE NORMAL
5 1 OCR_0001 OCR_0001 2447 2139 /dev/oracleasm/disks/ASMDISK2 CACHED MEMBER ONLINE NORMAL
5 2 OCR_0002 OCR_0002 2447 2138 /dev/oracleasm/disks/ASMDISK3 CACHED MEMBER ONLINE NORMAL
14 rows selected.
添加！
alter diskgroup DATA2 add
FAILGROUP DATA2_0000 DISK '/dev/oracleasm/disks/ASMDISK8'
FAILGROUP DATA2_0001 DISK '/dev/oracleasm/disks/ASMDISK9'
FAILGROUP DATA2_0002 DISK '/dev/oracleasm/disks/ASMDISK13'
rebalance power 0;
SQL> select group_number,disk_number,name,failgroup,total_mb,free_mb,path,mount_status,header_status,mode_status,state from v$asm_disk order by 1,2,3;
GROUP_NUMBER DISK_NUMBER NAME FAILGROUP TOTAL_MB FREE_MB PATH MOUNT_STAT HEADER_STA MODE_STATU STATE
------------ ----------- ---------- ---------- ---------- ---------- ------------------------------ ---------- ---------- ---------- ----------
1 0 ARCH_0000 ARCH_0000 4016 1635 /dev/oracleasm/disks/ASMDISK14 CACHED MEMBER ONLINE NORMAL
2 0 DATA1_0000 DATA1_0000 2447 741 /dev/oracleasm/disks/ASMDISK10 CACHED MEMBER ONLINE NORMAL
2 1 DATA1_0001 DATA1_0001 2447 740 /dev/oracleasm/disks/ASMDISK11 CACHED MEMBER ONLINE NORMAL
2 2 DATA1_0002 DATA1_0002 2447 743 /dev/oracleasm/disks/ASMDISK12 CACHED MEMBER ONLINE NORMAL
2 3 DATA1_0003 DATA1_0003 2447 740 /dev/oracleasm/disks/ASMDISK7 CACHED MEMBER ONLINE NORMAL
3 0 DATA2_0000 DATA2_0000 2447 2388 /dev/oracleasm/disks/ASMDISK4 CACHED MEMBER ONLINE NORMAL
3 1 DATA2_0001 DATA2_0001 2447 2386 /dev/oracleasm/disks/ASMDISK5 CACHED MEMBER ONLINE NORMAL
3 2 DATA2_0002 DATA2_0002 2447 2388 /dev/oracleasm/disks/ASMDISK6 CACHED MEMBER ONLINE NORMAL
3 3 DATA2_0003 DATA2_0000 2447 2393 /dev/oracleasm/disks/ASMDISK8 CACHED MEMBER ONLINE NORMAL
3 4 DATA2_0004 DATA2_0001 2447 2391 /dev/oracleasm/disks/ASMDISK9 CACHED MEMBER ONLINE NORMAL
3 5 DATA2_0005 DATA2_0002 2447 2394 /dev/oracleasm/disks/ASMDISK13 CACHED MEMBER ONLINE NORMAL
5 0 OCR_0000 OCR_0000 2447 2138 /dev/oracleasm/disks/ASMDISK1 CACHED MEMBER ONLINE NORMAL
5 1 OCR_0001 OCR_0001 2447 2139 /dev/oracleasm/disks/ASMDISK2 CACHED MEMBER ONLINE NORMAL
5 2 OCR_0002 OCR_0002 2447 2138 /dev/oracleasm/disks/ASMDISK3 CACHED MEMBER ONLINE NORMAL
14 rows selected.
对比一下normal冗余模式下三块盘和六块盘的异同:
相同点:都是存放两份数据，打散在不同的failgroup里面
不同点:三块盘的normal冗余模式，指定三个failgroup，只允许损坏一个failgroup，也就是只允许损坏一个磁盘（因为一个failgroup里面只含有一个磁盘）
六块盘的normal冗余模式，同样指定三个failgroup，只允许损坏一个failgroup，也就是只允许损坏(同一个failgroup里面的)两块盘.
SQL> select group_number,disk_number,failgroup from v$asm_disk where group_number=3 order by 1,3;
GROUP_NUMBER DISK_NUMBER FAILGROUP
------------ ----------- ------------------------------
3 3 DATA2_0000
3 0 DATA2_0000
3 1 DATA2_0001
3 4 DATA2_0001
3 2 DATA2_0002
3 5 DATA2_0002
6 rows selected.
GROUP_KFFXP DISK# EXTENT# TYPE
----------- ---------- ---------- ---------------------------
FAILGROUP1
3 0 2 Mirrored Copy
3 0 4 Primary Copy
3 0 9 Mirrored Copy
3 0 10 Primary Copy
3 3 1 Primary Copy
3 3 3 Mirrored Copy
3 3 6 Mirrored Copy
3 3 8 Primary Copy
3 3 14 Primary Copy
FAILGROUP2
3 1 0 Primary Copy
3 1 3 Primary Copy
3 1 4 Mirrored Copy
3 1 5 Mirrored Copy
3 1 9 Primary Copy
3 1 14 Mirrored Copy
3 4 1 Mirrored Copy
3 4 2 Primary Copy
3 4 7 Primary Copy
3 4 10 Mirrored Copy
3 4 11 Mirrored Copy
3 4 12 Mirrored Copy
3 4 13 Primary Copy
FAILGROUP3
3 2 5 Primary Copy
3 2 7 Mirrored Copy
3 2 11 Primary Copy
3 2 13 Mirrored Copy
3 5 0 Mirrored Copy
3 5 6 Primary Copy
3 5 8 Mirrored Copy
3 5 12 Primary Copy
30 rows selected.
第四阶段：测试实验DATA2 HIGH情况下，6块磁盘，观察failgroup情况；
drop tablespace GAO1 including contents and datafiles; SQL> alter diskgroup data2 dismount; alter diskgroup data2 mount; drop diskgroup data2; col path for a30 col name for a15 col failgroup for a14 col mount_status for a10 col header_status for a10 col mode_status for a10 col state for a10 set linesize 200 set pagesize 200 select group_number,disk_number,name,failgroup,total_mb,free_mb,path,mount_status,header_status,mode_status,state from v$asm_disk order by 1,2,3; GROUP_NUMBER DISK_NUMBER NAME FAILGROUP TOTAL_MB FREE_MB PATH MOUNT_STAT HEADER_STA MODE_STATU STATE ------------ ----------- --------------- -------------- ---------- ---------- ------------------------------ ---------- ---------- ---------- ---------- 0 0 0 0 /dev/oracleasm/disks/ASMDISK13 CLOSED FORMER ONLINE NORMAL 0 1 0 0 /dev/oracleasm/disks/ASMDISK9 CLOSED FORMER ONLINE NORMAL 0 2 0 0 /dev/oracleasm/disks/ASMDISK8 CLOSED FORMER ONLINE NORMAL 0 3 0 0 /dev/oracleasm/disks/ASMDISK6 CLOSED FORMER ONLINE NORMAL 0 4 0 0 /dev/oracleasm/disks/ASMDISK5 CLOSED FORMER ONLINE NORMAL 0 5 0 0 /dev/oracleasm/disks/ASMDISK4 CLOSED FORMER ONLINE NORMAL 1 0 ARCH_0000 ARCH_0000 4016 1635 /dev/oracleasm/disks/ASMDISK14 CACHED MEMBER ONLINE NORMAL 2 0 DATA1_0000 DATA1_0000 2447 741 /dev/oracleasm/disks/ASMDISK10 CACHED MEMBER ONLINE NORMAL 2 1 DATA1_0001 DATA1_0001 2447 740 /dev/oracleasm/disks/ASMDISK11 CACHED MEMBER ONLINE NORMAL 2 2 DATA1_0002 DATA1_0002 2447 743 /dev/oracleasm/disks/ASMDISK12 CACHED MEMBER ONLINE NORMAL 2 3 DATA1_0003 DATA1_0003 2447 740 /dev/oracleasm/disks/ASMDISK7 CACHED MEMBER ONLINE NORMAL 5 0 OCR_0000 OCR_0000 2447 2138 /dev/oracleasm/disks/ASMDISK1 CACHED MEMBER ONLINE NORMAL 5 1 OCR_0001 OCR_0001 2447 2139 /dev/oracleasm/disks/ASMDISK2 CACHED MEMBER ONLINE NORMAL 5 2 OCR_0002 OCR_0002 2447 2138 /dev/oracleasm/disks/ASMDISK3 CACHED MEMBER ONLINE NORMAL 14 rows selected. --alter diskgroup data1 rebalance power 6; select * from v$asm_operation; create diskgroup DATA2 high redundancy FAILGROUP fgroup1 disk '/dev/oracleasm/disks/ASMDISK13','/dev/oracleasm/disks/ASMDISK9' FAILGROUP fgroup2 disk '/dev/oracleasm/disks/ASMDISK8','/dev/oracleasm/disks/ASMDISK6' FAILGROUP fgroup3 disk '/dev/oracleasm/disks/ASMDISK5','/dev/oracleasm/disks/ASMDISK4' ; GROUP_NUMBER DISK_NUMBER NAME FAILGROUP TOTAL_MB FREE_MB PATH MOUNT_STAT HEADER_STA MODE_STATU STATE ------------ ----------- --------------- -------------- ---------- ---------- ------------------------------ ---------- ---------- ---------- ---------- 1 0 ARCH_0000 ARCH_0000 4016 1635 /dev/oracleasm/disks/ASMDISK14 CACHED MEMBER ONLINE NORMAL 2 0 DATA1_0000 DATA1_0000 2447 741 /dev/oracleasm/disks/ASMDISK10 CACHED MEMBER ONLINE NORMAL 2 1 DATA1_0001 DATA1_0001 2447 740 /dev/oracleasm/disks/ASMDISK11 CACHED MEMBER ONLINE NORMAL 2 2 DATA1_0002 DATA1_0002 2447 743 /dev/oracleasm/disks/ASMDISK12 CACHED MEMBER ONLINE NORMAL 2 3 DATA1_0003 DATA1_0003 2447 740 /dev/oracleasm/disks/ASMDISK7 CACHED MEMBER ONLINE NORMAL 3 0 DATA2_0000 FGROUP1 2447 2420 /dev/oracleasm/disks/ASMDISK13 CACHED MEMBER ONLINE NORMAL 3 1 DATA2_0001 FGROUP1 2447 2421 /dev/oracleasm/disks/ASMDISK9 CACHED MEMBER ONLINE NORMAL 3 2 DATA2_0002 FGROUP2 2447 2420 /dev/oracleasm/disks/ASMDISK8 CACHED MEMBER ONLINE NORMAL 3 3 DATA2_0003 FGROUP2 2447 2421 /dev/oracleasm/disks/ASMDISK6 CACHED MEMBER ONLINE NORMAL 3 4 DATA2_0004 FGROUP3 2447 2420 /dev/oracleasm/disks/ASMDISK5 CACHED MEMBER ONLINE NORMAL 3 5 DATA2_0005 FGROUP3 2447 2421 /dev/oracleasm/disks/ASMDISK4 CACHED MEMBER ONLINE NORMAL 5 0 OCR_0000 OCR_0000 2447 2138 /dev/oracleasm/disks/ASMDISK1 CACHED MEMBER ONLINE NORMAL 5 1 OCR_0001 OCR_0001 2447 2139 /dev/oracleasm/disks/ASMDISK2 CACHED MEMBER ONLINE NORMAL 5 2 OCR_0002 OCR_0002 2447 2138 /dev/oracleasm/disks/ASMDISK3 CACHED MEMBER ONLINE NORMAL 14 rows selected. select group_number,name,type,COMPATIBILITY from v$asm_diskgroup GROUP_NUMBER NAME TYPE COMPATIBILITY ------------ --------------- ------------------ -------------------- 1 ARCH EXTERN 11.2.0.0.0 2 DATA1 EXTERN 11.2.0.0.0 3 DATA2 HIGH 10.1.0.0.0 5 OCR NORMAL 11.2.0.0.0 high冗余三份数据： failgroup为单位，只允许坏掉两个failgroup里面的数据，是不会造成数据丢失的。 从oracle 11g版本开始,asm磁盘组会有两个新属性来兼容asm版本和数据库版本 http://blog.itpub.net/31397003/viewspace-2132859/ COMPATIBLE.ASM - The minimum version of the ASM software that can access the disk group. In 11g, the default setting is 10.1. COMPATIBLE.RDBMS - The minimum COMPATIBLE database initialization parameter setting for any database instance that uses the disk group. In 11g, the default setting is 10.1. SELECT group_number, name, value FROM v$asm_attribute where NAME like 'compatible%' ORDER BY group_number, name; GROUP_NUMBER NAME VALUE ------------ ---------------------------------------- ------------------------------ 1 compatible.asm 11.2.0.0.0 1 compatible.rdbms 10.1.0.0.0 2 compatible.asm 11.2.0.0.0 2 compatible.rdbms 10.1.0.0.0 5 compatible.asm 11.2.0.0.0 5 compatible.rdbms 10.1.0.0.0 6 rows selected. SELECT group_number, name, compatibility, database_compatibility FROM v$asm_diskgroup; GROUP_NUMBER NAME COMPATIBILITY DATABASE_COMPATIBILI ------------ ---------- -------------------- -------------------- 1 ARCH 11.2.0.0.0 10.1.0.0.0 2 DATA1 11.2.0.0.0 10.1.0.0.0 3 DATA2 10.1.0.0.0 10.1.0.0.0 5 OCR 11.2.0.0.0 10.1.0.0.0 create tablespace GAO1 datafile '+DATA2' size 14m SQL> select file_number,name from v$asm_alias where name like 'GAO%'; FILE_NUMBER NAME ----------- ---------------------------------------------------------------------- 256 GAO1.256.1057165987 0 DATA2_0000 FGROUP1 1 DATA2_0001 FGROUP1 2 DATA2_0002 FGROUP2 3 DATA2_0003 FGROUP2 4 DATA2_0004 FGROUP3 5 DATA2_0005 FGROUP3 select GROUP_KFFXP,disk_kffxp disk#, XNUM_KFFXP extent#, case lxn_kffxp when 0 then 'Primary Copy' when 1 then 'Mirrored Copy' when 2 then '2nd Mirrored Copy or metadata' else 'Unknown' END TYPE from x$kffxp where number_kffxp=256 and GROUP_KFFXP=3 order by 1,2,3; GROUP_KFFXP DISK# EXTENT# TYPE ----------- ---------- ---------- ----------------------------------- 3 0 0 Mirrored Copy 3 0 5 Primary Copy 3 0 8 Mirrored Copy 3 0 9 2nd Mirrored Copy or metadata 3 0 10 Mirrored Copy 3 0 11 Primary Copy 3 0 12 Mirrored Copy 3 1 1 Primary Copy 3 1 2 Mirrored Copy 3 1 3 Mirrored Copy 3 1 4 2nd Mirrored Copy or metadata 3 1 6 2nd Mirrored Copy or metadata 3 1 7 Primary Copy 3 1 13 Primary Copy 3 1 14 Mirrored Copy 3 2 3 Primary Copy 3 2 4 Mirrored Copy 3 2 5 2nd Mirrored Copy or metadata 3 2 7 2nd Mirrored Copy or metadata 3 2 8 2nd Mirrored Copy or metadata 3 2 9 Primary Copy 3 3 0 Primary Copy 3 3 1 2nd Mirrored Copy or metadata 3 3 2 2nd Mirrored Copy or metadata 3 3 6 Primary Copy 3 3 10 2nd Mirrored Copy or metadata 3 3 11 Mirrored Copy 3 3 12 Primary Copy 3 3 13 2nd Mirrored Copy or metadata 3 3 14 2nd Mirrored Copy or metadata 3 4 1 Mirrored Copy 3 4 4 Primary Copy 3 4 6 Mirrored Copy 3 4 9 Mirrored Copy 3 4 10 Primary Copy 3 4 11 2nd Mirrored Copy or metadata 3 4 13 Mirrored Copy 3 5 0 2nd Mirrored Copy or metadata 3 5 2 Primary Copy 3 5 3 2nd Mirrored Copy or metadata 3 5 5 Mirrored Copy 3 5 7 Mirrored Copy 3 5 8 Primary Copy 3 5 12 2nd Mirrored Copy or metadata 3 5 14 Primary Copy 45 rows selected. 可以发现每个FAILGROUP组存有45/3=15条记录！ 整个数据文件占用15个AU即15个extents分配，被3份冗余！ 因此high可以丢失2份所有Failgroup数据。