Expert Oracle Exadata - Parent Directory

CHAPTER 9 RECOVERING EXADATASYS:+ASM2> select dg.name, oper.operation, oper.statefrom gv$asm_operation oper,gv$asm_diskgroup dgwhere dg.group_number = oper.group_numberand dg.inst_id = oper.inst_id;NAMEOPERATION-------------------------------------------------- ----------SCRATCH_DGONLINChecking for the online/offline state of a disk is a simple matter of running the following query fromSQL*Plus. In the listing below you can see that the SCRATCH_CD_05_CELL01 disk is offline by itsMOUNT_STATE of MISSING and HEADER_STATUS of UNKNOWN:SYS:+ASM2> select d.name, d.MOUNT_STATUS, d.HEADER_STATUS, d.STATEfrom v$asm_disk dwhere d.name like 'SCRATCH%'order by 1;NAMEMOUNT_S HEADER_STATU STATE-------------------------------------------------- ------- ------------ ----------SCRATCH_CD_05_CELL01 MISSING UNKNOWN NORMALSCRATCH_CD_05_CELL02 CACHED MEMBER NORMALSCRATCH_CD_05_CELL03 CACHED MEMBER NORMALStill, perhaps a better way of checking the status of all disks in the SCRATCH_DG disk group would be tocheck the mode_status in V$ASM_DISK_STAT. The following listing shows that all grid disks in theSCRATCH_DG disk group are online:SYS:+ASM2> select name, mode_status from v$asm_disk_stat where name like 'SCRATCH%';NAMEMODE_ST-------------------------------------------------- -------SCRATCH_CD_05_CELL03ONLINESCRATCH_CD_05_CELL01ONLINESCRATCH_CD_05_CELL02ONLINEThe next thing we’ll look at is the disk repair timer. Recall that the disk group attributedisk_repair_time determines the amount of time ASM will wait before it permanently removes a diskfrom the disk group and rebalances the data to the surviving grid disks when read/write errors occur.Before taking a disk offline we should check to see that this timer is going to give us enough time to bringthe disk back online before ASM automatically drops it. This attribute can be displayed using SQL*Plusand running the following query. (By the way, the V$ASM views are visible whether you are connected toan ASM instance or a database instance.)SYS:+ASM2> select dg.name "DiskGoup",attr.name,attr.valuefrom v$asm_diskgroup dg,v$asm_attribute attrwhere dg.group_number = attr.group_numberand attr.name = 'disk_repair_time';3041