Hoy vamos a ver un a entrada sencilla sobre la redundancia en los voting disk.
Supongamos tenemos un RAC con un votedisk en un grupo de ASM externo.
[grid@rac1 ~]$ crsctl query css votedisk
## STATE File Universal Id File Name Disk group
-- ----- ----------------- --------- ---------
1. ONLINE 9711d76755664f81bfeac1daf04aefcf (/dev/oracleasm/disks/OCRVOTING) [OCRVOTING]
Located 1 voting disk(s).
[grid@rac1 ~]$ ocrcheck
Status of Oracle Cluster Registry is as follows :
Version : 3
Total space (kbytes) : 262120
Used space (kbytes) : 2692
Available space (kbytes) : 259428
ID : 241611837
Device/File Name : +OCRVOTING
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 bypassed due to non-privileged user
Nosotros tenemos un DISKGROUP de ASM con redundancia HIGH , y queremos llevar nuestro votingdisk a este disco .
column name format a20;
column state format a20;
column type format a20;
select NAME,STATE,TYPE from v$asm_diskgroup;
NAME STATE TYPE
-------------------- -------------------- --------------------
OCRVOTING MOUNTED EXTERN
REDO DISMOUNTED
DATA MOUNTED HIGH
ACFS DISMOUNTED
OCRASM MOUNTED EXTERN
Ejecutamos el comando crsctl replace votedisk +DATA y recibiremos el siguiente error:
[grid@rac1 ~]$ crsctl replace votedisk +DATA
Failed to create voting files on disk group DATA.
Change to configuration failed, but was successfully rolled back.
CRS-4000: Command Replace failed, or completed with errors.
¿Como podemos saber mas de este error?
Vamos a mirar el alert.log del asm
tail -900 /u01/app/oracle/diag/asm/+asm/+ASM1/trace/alert_+ASM1.log
TE: [crsctl.bin@rac1.pamplona.name (TNS V1-V3) 20094] opening OCR file
Wed Aug 19 11:39:20 2015
NOTE: updated gpnp profile ASM diskstring: /dev/oracleasm/disks/*
Wed Aug 19 11:39:20 2015
NOTE: Creating voting files in diskgroup DATA
Wed Aug 19 11:39:20 2015
NOTE: Voting File refresh pending for group 3/0xe73953ba (DATA)
NOTE: Attempting voting file creation in diskgroup DATA
NOTE: voting file allocation on grp 3 disk DATA_0000
NOTE: voting file allocation on grp 3 disk DATA_0001
NOTE: voting file allocation on grp 3 disk DATA_0002
ERROR: Voting file allocation failed for group DATA
Errors in file /u01/app/oracle/diag/asm/+asm/+ASM1/trace/+ASM1_ora_20102.trc:
Y que error tenemos en este fichero de traza?
cat /u01/app/oracle/diag/asm/+asm/+ASM1/trace/+ASM1_ora_20102.trc
..
.
*** 2015-08-19 11:39:24.754
Updating headers of disk /dev/oracleasm/disks/ASM03 with 96 128
PST-new:0x7f6053f8fe60:0x9f1d9478:45:
/dev/oracleasm/disks/ASM03:67f2cd24882e4f46bfe07f85554e0d33:
ORA-15274: Not enough failgroups (5) to create voting files
Como podemos ver, el GRID ha visto que nuestro grupo de ASM no cuenta con 5 failgroups ( solamente cuenta con 3 discos), con lo que ha echado atrás la operación.
Que pasaría si quisiesemos llevarlo a otro external?
Si queremos llevarlo a otro external veremos que funciona correctamente.
[grid@rac1 ~]$ crsctl replace votedisk +OCRASM
Successful addition of voting disk 5f3f3404c2cd4f24bfa6ca5de9494bba.
Successful deletion of voting disk 9711d76755664f81bfeac1daf04aefcf.
Successfully replaced voting disk group with +OCRASM.
CRS-4266: Voting file(s) successfully replaced
Y si quisiéramos añadir otra ASM con redundancia external?
[grid@rac1 ~]$ crsctl add css votedisk +OCRVOTING
CRS-4671: This command is not supported for ASM diskgroups.
CRS-4000: Command Add failed, or completed with errors.
Vemos como tampoco nos permite el poner el voting disk en 2 ASM DISKGROUPS
Conclusiones
Podemos beneficiarnos (y es aconsejable) de la redundancia del ASM para el voting disk, pero, hay que tener en cuenta que :
- No podemos mezclar voting disk en asm y no asm
- Voting disk necesita unos determinados failugre groups en ASM
- External: No ha dependencia ya que se gestiona externamente
- Normal: Deberemos de tener un mínimo de 3 failgroups
- External: deberemos de terner un mínimo de 5 failgroups
- Si usamos ASM para los voting disk la redundancia la marca el ASM
