Expert Oracle Exadata - Parent Directory

CHAPTER 9 RECOVERING EXADATATable 9-3. Disk Status DefinitionsStatusNormalPredictive FailurePoor PerformanceDescriptionThe drive is healthy.The disk is still working but likely to fail soon and should be replaced as soon aspossible.The disk is exhibiting extremely poor performance and should be replaced.Predictive FailureIf a disk status shows Predictive Failure, ASM will automatically drop the grid disks from the drive andrebalance data to other disks in the disk group according to the redundancy policy of the affected diskgroups that use the drive. Once ASM has finished rebalancing and completed the drop operation, youcan replace the disk drive. The following listing can be used to track the status of the ASM disk. A statusof Offline indicates that ASM has not yet finished rebalancing the disk group. Once the rebalance iscomplete, the disk will no longer appear in the listing. By the way, tailing the ASM alert log is also anexcellent way of checking the progress of the drop.SYS:+ASM2>select name, mode_statusfrom v$asm_disk_statwhere name like 'SCRATCH%'order by 1;NAMEMODE_ST-------------------------------------------------- -------SCRATCH_CD_05_CELL01ONLINESCRATCH_CD_05_CELL02ONLINESCRATCH_CD_05_CELL03OFFLINE■ Caution: The first two physical disks in the storage cell also contain the Linux operating system. The O/Spartitions on these two disks are configured as mirrors of one another. If one of these disks fails, the data must bein sync with the mirror disk before you remove it. Use the CellCLI command alter cell validateconfiguration to verify that no madm errors exist before replacing the disk.The CellCLI command VALIDATE CONFIGURATION performs this verification for you:CellCLI> ALTER CELL VALIDATE CONFIGURATIONCell enkcel01 successfully altered311