環境：3台虛擬機 RHEL 7.3 + Oracle RAC 11.2.0.4
問題現象：RAC運行正常，ASM磁盤組Normal冗余，有failgroup整體故障，有failgroup配置錯誤。
溫馨提示：本文並不是市場上任何一款商業的一體機產品，只是我為了學習這類分布式存儲架構自己模擬的實驗環境，為了區分我暫時稱之為xData吧_。
1.問題現象確認
SQL> select group_number, name, total_mb, free_mb, USABLE_FILE_MB, offline_disks, state, type from v$asm_diskgroup;
GROUP_NUMBER NAME TOTAL_MB FREE_MB USABLE_FILE_MB OFFLINE_DISKS STATE TYPE
------------ ------------------------------ ---------- ---------- -------------- ------------- ---------------------- ----------
1 CRS 2000 1170 585 0 MOUNTED NORMAL
2 DATA 40960 35652 7586 0 MOUNTED NORMAL
SQL> select group_number, disk_number, name, path, failgroup, mode_status, voting_file from v$asm_disk order by 1, 2;
GROUP_NUMBER DISK_NUMBER NAME PATH FAILGROUP MODE_STATUS VO
------------ ----------- ------------------------------ ----------------------- -------------------- -------------- --
0 0 /dev/CELL01-data2 ONLINE N
0 1 /dev/CELL01-data1 ONLINE N
0 2 /dev/CELL01-crs1 ONLINE Y
1 1 CRS_0001 /dev/CELL02-crs2 CRS_0001 ONLINE Y
1 2 CRS_0002 /dev/CELL03-crs3 CRS_0002 ONLINE Y
2 0 DATA_0000 /dev/CELL03-data1 DATA_0000 ONLINE N
2 1 DATA_0001 /dev/CELL03-data2 DATA_0001 ONLINE N
2 2 DATA_0002 /dev/CELL02-data1 CELL02 ONLINE N
2 3 DATA_0003 /dev/CELL02-data2 CELL02 ONLINE N
9 rows selected.
可以看到不但CELL01節點的所有盤被刪除，而且CELL03節點的數據盤，failgroup目前也配置不正確！
2.重新加入CELL01的盤
由於時間超過默認的3.6h，offline的盤已經被刪除，只有重新加入CELL01的盤才可以。alter diskgroup CRS add disk '/dev/CELL01-crs1';
alter diskgroup DATA ADD FAILGROUP CELL01 disk '/dev/CELL01-data1', '/dev/CELL01-data2' rebalance power 5;
直接這樣加盤很可能會遇到下面這類錯誤，因為這些盤之前是被使用過的：
SQL> alter diskgroup CRS add disk '/dev/CELL01-crs1';
alter diskgroup CRS add disk '/dev/CELL01-crs1'
*
ERROR at line 1:
ORA-15032: not all alterations performed
ORA-15033: disk '/dev/CELL01-crs1' belongs to diskgroup "CRS"
這個問題可以通過dd盤頭，也可以加盤嘗試加force參數來解決，我這里選擇dd盤頭的方式：
[root@db01 ~]# dd if=/dev/zero of=/dev/CELL01-crs1 bs=8k count=1000
1000+0 records in
1000+0 records out
8192000 bytes (8.2 MB) copied, 0.0691801 s, 118 MB/s
dd盤頭之后再次嘗試添加就可以順利完成：
SQL> alter diskgroup CRS add disk '/dev/CELL01-crs1';
Diskgroup altered.
同樣的，將CELL01的數據盤也重新加入到DATA磁盤組中，failgroup名稱為CELL01:
SQL> alter diskgroup DATA ADD FAILGROUP CELL01 disk '/dev/CELL01-data1', '/dev/CELL01-data2' rebalance power 5;
Diskgroup altered.
通過v$asm_operation視圖可以查看磁盤重新平衡的進度，直到下面的查詢不再返回結果說明重平衡完成：
SQL> select * from v$asm_operation;
GROUP_NUMBER OPERATION STATE POWER ACTUAL SOFAR EST_WORK EST_RATE EST_MINUTES ERROR_CODE
------------ ---------- -------- ---------- ---------- ---------- ---------- ---------- ----------- --------------------
2 REBAL RUN 5 5 366 529 348 0
SQL> select * from v$asm_operation;
no rows selected
3.修改failgroup的配置
CELL03的數據盤，failgroup目前配置還不正確。SQL> alter diskgroup DATA drop disk DATA_0000, DATA_0001;
Diskgroup altered.
查詢v$asm_operation視圖可以查看磁盤重新平衡的進度，完成后再重新加回磁盤組，指定確切的failgroup(CELL03)：
SQL> alter diskgroup DATA ADD FAILGROUP CELL03 disk '/dev/CELL03-data1', '/dev/CELL03-data2' rebalance power 5;
Diskgroup altered.
再次關注重平衡進度，最后查詢一切正常，結果如下：
SQL> col path for a50
SQL> select group_number, disk_number, name, path, failgroup, mode_status, voting_file from v$asm_disk order by 1, 2;
GROUP_NUMBER DISK_NUMBER NAME PATH FAILGROUP MODE_STATUS VO
------------ ----------- ------------------------------ ----------------------- -------------------- -------------- --
1 0 CRS_0000 /dev/CELL01-crs1 CRS_0000 ONLINE Y
1 1 CRS_0001 /dev/CELL02-crs2 CRS_0001 ONLINE Y
1 2 CRS_0002 /dev/CELL03-crs3 CRS_0002 ONLINE Y
2 0 DATA_0000 /dev/CELL03-data1 CELL03 ONLINE N
2 1 DATA_0001 /dev/CELL03-data2 CELL03 ONLINE N
2 2 DATA_0002 /dev/CELL02-data1 CELL02 ONLINE N
2 3 DATA_0003 /dev/CELL02-data2 CELL02 ONLINE N
2 4 DATA_0004 /dev/CELL01-data1 CELL01 ONLINE N
2 5 DATA_0005 /dev/CELL01-data2 CELL01 ONLINE N
9 rows selected.
SQL> select group_number, name, total_mb, free_mb, USABLE_FILE_MB, offline_disks, state, type from v$asm_diskgroup;
GROUP_NUMBER NAME TOTAL_MB FREE_MB USABLE_FILE_MB OFFLINE_DISKS STATE TYPE
------------ ------------------------------ ---------- ---------- -------------- ------------- ---------------------- ----------
1 CRS 3000 2033 516 0 MOUNTED NORMAL
2 DATA 61440 56012 17766 0 MOUNTED NORMAL
說明：一般我會將磁盤組的兼容性參數設置為11.2，如有特殊需求，還可以設置disk_repair_time（默認3.6h）。
SQL> col COMPATIBILITY for a30
SQL> col DATABASE_COMPATIBILITY for a30
SQL> select NAME, COMPATIBILITY, DATABASE_COMPATIBILITY from v$asm_diskgroup;
NAME COMPATIBILITY DATABASE_COMPATIBILITY
------------------------------ ------------------------------ ------------------------------
CRS 11.2.0.0.0 11.2.0.0.0
DATA 11.2.0.0.0 11.2.0.0.0
--設置DATA磁盤組disk_repair_time(可理解為磁盤離線刪除的時間)屬性為4.5h
SQL> ALTER DISKGROUP data SET ATTRIBUTE 'disk_repair_time' = '4.5h';
Diskgroup altered.