12c New Feature – Multiple Flash Device Support for Database Smart Flash Cache

Not sure anyone has seen or know about this 12c feature, it allows the grouping/aggregation of flash devices into a volume, I mentioned it during a SSD discussion at IOUG

Essentially, this feature allows a database instance to access and combine multiple flash devices for Database Smart Flash Cache without the need for a volume manager, this way you no longer need to incur the expense or management overhead of a logical volume manager in order to use multiple flash devices for Database Smart Flash Cache.

For example, Flash devices /dev/sdj, /dev/sdk, and /dev/sdl, you can set the following init.ora parameter for aggregation:

DB_FLASH_CACHE_FILE = /dev/sdj, /dev/sdk, /dev/sdl

DB_FLASH_CACHE_SIZE = 32G, 32G, 64G

The V$FLASHFILESTAT view can be used to determine the cumulative latency and read counts of each file and compute the average latency.

You can use ALTER SYSTEM to set DB_FLASH_CACHE_SIZE to zero for each flash device you wish to disable. You can also use ALTER SYSTEM to set the size for any disabled flash device back to its original size to reenable it. However, dynamically changing the size of Database Smart Flash Cache is not supported.