在11g 安裝過程中默認只能指定一個 dg 用來存儲：crs ，voting
但是oracle 官方一般建議我們這麼來配置：
1、當ocr沒有配置鏡像，或者冗余存儲時 最少3個ocr 。
如果底層存儲不是RAID的話，oracle建議鏡像OCR，鏡像可以避免單點故障。
■ At least two OCR locations if OCR is configured on an Oracle ASM disk group.
You should configure OCR in two independent disk groups. Typically this is the
work area and the recovery area.
2、如果ocr 配置在oracle asm disk group上時，建議最少兩個ocr 位置
ocr 應當配置在兩個單獨的 disk group
■ At least two OCR locations if OCR is configured on mirrored hardware or
third-party mirrored volumes.
3、如果ocr 配置在有鏡像的硬件或者在第3方的鏡像卷上時也建議最少冗余2個ocr
eg：添加多個ocr （最多5個）
ocrconfig -add +asm_disk_group| file_name
ocrconfig -delete +ASM_disk_group| file_name
[root@vmrac1 ~]# ocrcheck
Status of Oracle Cluster Registry is as follows :
Version : 3
Total space (kbytes) : 262120
Used space (kbytes) : 3540
Available space (kbytes) : 258580
ID : 1902812549
Device/File Name : +CRS
Device/File integrity check succeeded
Device/File not configured
Device/File not configured
Device/File not configured
Device/File not configured
Cluster registry integrity check succeeded
Logical corruption check succeeded
[root@vmrac1 ~]# ocrconfig -add +ARCH --------------------------添加一個新的ocr +ARCH
[root@vmrac1 ~]# ocrcheck ------------------------------檢查後已經成功添加
Status of Oracle Cluster Registry is as follows :
Version : 3
Total space (kbytes) : 262120
Used space (kbytes) : 3540
Available space (kbytes) : 258580
ID : 1902812549
Device/File Name : +CRS
Device/File integrity check succeeded
Device/File Name : +ARCH
Device/File integrity check succeeded
Device/File not configured
Device/File not configured
Device/File not configured
Cluster registry integrity check succeeded
Logical corruption check succeeded
同理再添加幾個 dg
[root@vmrac1 ~]# ocrconfig -add +DATANEW
[root@vmrac1 ~]# ocrcheck
Status of Oracle Cluster Registry is as follows :
Version : 3
Total space (kbytes) : 262120
Used space (kbytes) : 3540
Available space (kbytes) : 258580
ID : 1902812549
Device/File Name : +CRS
Device/File integrity check succeeded
Device/File Name : +ARCH
Device/File integrity check succeeded
Device/File Name : +DATANEW
Device/File integrity check succeeded
Device/File not configured
Device/File not configured
Cluster registry integrity check succeeded
Logical corruption check succeeded
[root@vmrac1 ~]# ocrconfig -add +FLASH
[root@vmrac1 ~]# orcheck
-bash: orcheck: command not found
[root@vmrac1 ~]# ocrcheck
Status of Oracle Cluster Registry is as follows :
Version : 3
Total space (kbytes) : 262120
Used space (kbytes) : 3540
Available space (kbytes) : 258580
ID : 1902812549
Device/File Name : +CRS
Device/File integrity check succeeded
Device/File Name : +ARCH
Device/File integrity check succeeded
Device/File Name : +DATANEW
Device/File integrity check succeeded
Device/File Name : +FLASH
Device/File integrity check succeeded
Device/File not configured
Cluster registry integrity check succeeded
Logical corruption check succeeded
[root@vmrac1 ~]# ocrcheck
Status of Oracle Cluster Registry is as follows :
Version : 3
Total space (kbytes) : 262120
Used space (kbytes) : 3540
Available space (kbytes) : 258580
ID : 1902812549
Device/File Name : +CRS
Device/File integrity check succeeded
Device/File Name : +ARCH
Device/File integrity check succeeded
Device/File Name : +DATANEW
Device/File integrity check succeeded
Device/File Name : +FLASH
Device/File integrity check succeeded
Device/File not configured
Cluster registry integrity check succeeded
Logical corruption check succeeded
[root@vmrac1 ~]# ocrcheck -local
Status of Oracle Local Registry is as follows :
Version : 3
Total space (kbytes) : 262120
Used space (kbytes) : 2728
Available space (kbytes) : 259392
ID : 935756415
Device/File Name : /u02/app/11.2.0.3/grid/cdata/vmrac1.olr
Device/File integrity check succeeded
Local registry integrity check succeeded
Logical corruption check succeeded
------------這裡我們再來看下ocr 的配置信息 ，配置文件在Linux環境下位於 /etc/oracle/ocr.loc
[root@vmrac1 ~]# cd /etc/oracle
[root@vmrac1 oracle]# ls
lastgasp ocr.loc ocr.loc.orig olr.loc olr.loc.bkp olr.loc.orig oprocd scls_scr setasmgid
[root@vmrac1 oracle]# more ocr.loc
#Device/file getting replaced by device +FLASH
ocrconfig_loc=+CRS
ocrmirrorconfig_loc=+ARCH ----------新添加的 ocr 鏡像組
ocrconfig_loc3=+DATANEW
ocrconfig_loc4=+FLASH
local_only=false
[root@vmrac1 oracle]# more olr.loc
olrconfig_loc=/u02/app/11.2.0.3/grid/cdata/vmrac1.olr
crs_home=/u02/app/11.2.0.3/grid
-----------這裡處理添加新的ocr外，我們也可以替換老的 ocr dg：
[root@vmrac1 oracle]# ocrconfig -replace +ARCH -replacement +FLASH
[root@vmrac1 oracle]# ocrcheck
Status of Oracle Cluster Registry is as follows :
Version : 3
Total space (kbytes) : 262120
Used space (kbytes) : 3540
Available space (kbytes) : 258580
ID : 1902812549
Device/File Name : +CRS
Device/File integrity check succeeded
Device/File Name : +FLASH
Device/File integrity check succeeded
Device/File not configured
Device/File not configured
Device/File not configured
Cluster registry integrity check succeeded
Logical corruption check succeeded
[root@vmrac1 oracle]# ocrconfig -replace +FLASH -replacement +ARCH
[root@vmrac1 oracle]# ocrcheck
Status of Oracle Cluster Registry is as follows :
Version : 3
Total space (kbytes) : 262120
Used space (kbytes) : 3540
Available space (kbytes) : 258580
ID : 1902812549
Device/File Name : +CRS
Device/File integrity check succeeded
Device/File Name : +ARCH
Device/File integrity check succeeded
Device/File not configured
Device/File not configured
Device/File not configured
Cluster registry integrity check succeeded
Logical corruption check succeeded
[root@vmrac1 oracle]#
---------------------注意：當 只有一個 ocr dg 時以上命令會報錯：
[root@vmrac1 oracle]# ocrcheck
Status of Oracle Cluster Registry is as follows :
Version : 3
Total space (kbytes) : 262120
Used space (kbytes) : 3540
Available space (kbytes) : 258580
ID : 1902812549
Device/File Name : +CRS
Device/File integrity check succeeded
Device/File not configured
Device/File not configured
Device/File not configured
Device/File not configured
Cluster registry integrity check succeeded
Logical corruption check succeeded
[root@vmrac1 oracle]# ocrconfig -replace +CRS -replacement +ARCH
PROT-28: Cannot delete or replace the only configured Oracle Cluster Registry location
[root@vmrac1 oracle]#
正確做法：
如果當前的ocr 少於2個 ，則上述ocr 的替換命令會出錯
如果只有一個ocr 時我們可以先添加一個ocr ，再刪除原來的ocr
# ocrconfig -add new_OCR_location
# ocrconfig -delete current_OCR_location
