Disable cache disk

[Yves Crespin <crespin.quartz@wanadoo.fr>]

Hello,

I write a lot of files on a USB disk for video monitoring archiving.
The write program is faster than the USB.
Cache disk take all RAM and kernel start swapping and everything become 
very slow.
1/ is-it possible to *really* be synchronize. I prefer to have a blocked 
write() than use cache and get swap!
2/ is-it possible to disable cache disk ?

Thanks,

Yves

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