Server :: The CFQ Scheduler And "low_latency" Option?

I the Linux kernel 2.6.32, The CFQ scheduler has been changed as you probably know. They insert the 'low_latency" mode in it.I read that this option, actually limits the affect of the dirty data write from the buffer cache while the system doing sync IO.

From url:

Quote:

"the amount of async writeback sent to the device will be limited by the time since that last sync IO." "limiting the damage that the async IO can do while sync IO is also happening"

I also read that this option is not recommended to Database server.As I know, DB writes his DB files with O_DIRECT and won't write to the Filesustem buffer cache.SO this option don't need do bother him.