multiplexing redo logs

[Roshan]

Hello Erman,

kindly advise whether we need to multiplex redo logs on Exadata? Will this affect performance? In case write/read on redo logs is slow, Oracle will eventually query the flash cache log in case of bottleneck.

https://www.oracle.com/webfolder/technetwork/tutorials/demos/db/exadata/exadatav2/Exadata_Smart_Flash_Log/data/downloads/flash_log_estudy.pdf

Regards,

Roshan

[ErmanArslansOracleBlog]

Smart flash log is there for decreasing the latency.

*It is important note that the best practices and configuration recommendations for redo log sizing and
mirroring do not change when using Exadata Smart Flash Log.

And yes you can mirror them.. But ->
*With the release of the Smart Flash Log feature in 11.2.2.4, redo logs should never be placed on flash grid disks. Smart Flash Log leverages both hard disks and flash devices with intelligent caching to achieve the fastest possible redo write performance, optimizations which are lost if redo logs are simply placed on flash grid disks.

I guess these answer your question.

See -> Oracle Exadata Database Machine Setup/Configuration Best Practices(Doc ID 1274318.1)

[ErmanArslansOracleBlog]

Also run exachk when your redos are not multiplexed and check the recommendation there..

[Roshan]

Thanks for the update.