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Identification of Underperforming Disks feature in Exadata (Doc ID 1509105.1)

Last updated on AUGUST 20, 2020

Applies to:

Oracle Exadata Storage Server Software
Exadata X3-2 Hardware
Enterprise Manager Base Platform - Version to [Release 12.1]
Exadata X5-2 Hardware
Linux x86-64


Starting with Exadata version, an underperforming disk can be automatically identified and removed from the active configuration. Underperforming disks affect the overall performance because work is distributed equally to all disks. For example, if a disk is performing 30% slower than other disks, then the entire system's I/O capacity will be 30% lower.

When an underperforming disk is detected, Oracle Exadata Database Machine performs a set of performance tests. If the problem with the disk is temporary and it passes the tests, the disk is brought back into the configuration. If the disk does not pass the tests, it is marked as failed and an Automatic Service Request (ASR) is opened to replace the disk.

This feature applies to both hard disks and flash disks.


About storage cell software processes

Cell Server (CELLSRV) is the main component of Exadata software, that services I/O requests and provides advanced Exadata services, such as predicate processing offload. CELLSRV is implemented as a multithread process and should be expected to use the largest portion of processor cycles on a storage cell.

Management Server (MS) provides standalone storage cell management and configuration.


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In this Document
 About storage cell software processes
 Disk state changes
 Possibly underperforming - confined online
 Prepare for test - confined offline
 Under stress test
 Poor performance - drop force
 All well - back to normal
 Automatic Service Request
 Disk confinement triggers

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