Last weekend, an Exadata storage server flashdisk entered the predictive failure state. The flashdisk is used by the flashcache and has a griddisk which is a member of a normal redundancy diskgroup…

Question

Options

• AIdentify the griddisk on the predictive failure flashdisk and drop it from the associated ASM diskgroup
• BVerify that the griddisk located on the predictive failure flashdisk has been successfully dropped from
• CDrop the flashcache on the cell and re-create it using all but the predictive failure flashdisk.
• DSafely power off the cell containing the predictive failure flashdlsk.
• EReplace the predictive failure flashdisk.
• FPower up the cell containing the replaced flashdlsk and activate all grlddlsks.
• GDrop the flashcache on the cell and re-create it using all flashdlsks.
• HCreate a new griddisk on the replaced flashdisk.

• A
  6% (2)
• B
  80% (28)
• C
  3% (1)
• H
  11% (4)

Explanation

• Exadata monitors for the number of media and other disk/flash failures (e.g. an I/O write failure due to physical media damage). If there are too many of those, Exadata is 'predicting' that it will soon fail and it takes it out of the system. * Exadata Server, that runs on the storage cells, monitors disk health and performance. If the disk performance degrades it can put it into proactive failure mode. It also monitors for predictive failures based on the disk's SMART (Self-monitoring, Analysis and Reporting Technology) data. In both cases, the Exadata Server notifies XDMG to take those disks offline. When a faulty disk is replacedf on the storage cell, the Exadata Server will recrate all grid disks on a new disk. It will then notify XDMG to bring those grid disks online or add them back to disk groups, in case they were already dropped. * ASM is a critical component of the Exadata software stack. It is also a bit different - compared to non-Exadata environments. It still manages your disk groups, but builds those with grid disks. It still takes care of disk errors, but also handles predictive disk failures. It doesn't like external redundancy and ACFS, but it makes the disk group smart scan capable.

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