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Spotlight on Oracle 10.4 - Release Notes

Exadata Smart Flash Cache

This page shows usage of the Flash Cache.

The data is sourced from CellCLI where the objectType is FLASHCACHE.

Note: Spotlight on Oracle RAC may include monitoring of Exadata systems depending on the license purchased.

To open the Smart Flash Cache page

  1. Select the Spotlight on Oracle RAC connection in the Spotlight Browser.
  2. Click Exadata | Smart Flash Cache.

Smart Flash Cache Statistics Chart

Notes:

  • Every chart has a legend (list of symbols) to its right that describes the various series (line graphs) on the chart.
  • Click an item in the legend to highlight its series (line) in the chart. Click a second time to return the series to its normal appearance.
  • Move the mouse pointer over an item in the legend to view the current value for that series within the chart.
Data Description
Inserts The number of megabytes inserted into the flash cache.
Hits The number of megabytes successfully found in the flash cache.
Evictions The number of megabytes evicted from the flash cache to make room for other data.
Misses The number of megabytes not found in the flash cache, that had to be retrieved from disk.
Skips The number of megabytes retrieved from the Hard Disk (bypassing the Flash Cache).

Smart Flash Cache Usage by Segments Grid

Column Description
Object Number The object number.
Object Name The name of the object (available only for the currently connected database)
ESFC Type
Value Description
None Do not put the object in the Exadata Smart Flash Cache (ESFC).
Default Put the object in the Exadata Smart Flash Cache (ESFC) if space is available.
Keep Keep the object in the Exadata Smart Flash Cache (ESFC).
Non ESFC IO (Miss Count) The number of misses: requests for objects from the flash cache, not found in the flash cache.
ESFC IO (Hit Count) The number of hits: requests for objects from the flash cache successfully found in the flash cache.
% ESFC Hits

The proportion of Exadata Smart Flash Cache (ESFC) hits that are successful.

Hits are successful when the requested data is found in the Smart Flash Cache. Hits are unsuccessful (Misses) if the requested data needs to be retrieved from the Exadata Storage Servers (Cells) because it cannot be found in the Smart Flash Cache.

% ESFC Time Saved

An indicator of the time saved by the Exadata Smart Flash Cache (ESFC).

The proportion of:

  • The time it would have taken to process the Exadata Smart Flash Cache I/O from Hard Disk minus
  • The time it took to process the Exadata Smart Flash Cache I/O

over

  • The total time it took to process these IOs from Hard Disk plus
  • The time it took to process the Hard Disk I/O
Database ID The database the object is from (database id)
Database name The database the object is from (database name)

Smart Flash Cache Statistics Grid

Shows Cell Statistics relevant to the Flash Cache broken down by the Cell Host.

Column Description
Cell Host The host name of the Exadata Storage Server (Cell).
Statistic Name The name of the statistic.
Statistic Value The statistical value.
Unit The unit of measurement used in calculating the statistic.

 

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