Re: Inconsistent file IO times on AWR report


On 05/05/2010 16:52, Neil Kodner wrote:
So lets say that we're not currently using directio - is there a way to find out how much of our physical RAM is being used to cache filesystem data?
I'm not sure about Solaris, in linux you'd use the /proc/meminfo file to find out.
Are there any drawbacks to enabling directio on our oracle data volumes? This is a pure OLTP system with some overnight batch jobs.
As always, it depends. You'd be loosing the FS cache and should take that into consideration while sizing the SGA. In addition the FS cache can cache stuff that Oracle won't cache, like direct path physical reads. 

Is directio appropriate for data warehouses as well?

See above.

Harel Safra
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